X-Git-Url: http://pileus.org/git/?a=blobdiff_plain;f=fetchmail-FAQ.html;h=6b425ea2c376cc9b7d049e76044f250bcaa9c6be;hb=f6c7034fdbeb25d7d8eb0e62c0fe5de563eb7b55;hp=3760fe77e4aad6b8259b58cb1cafa668ef973078;hpb=c260a67eb2a4a93567a7a975b6ebe92204fc9b49;p=~andy%2Ffetchmail diff --git a/fetchmail-FAQ.html b/fetchmail-FAQ.html index 3760fe77..6b425ea2 100644 --- a/fetchmail-FAQ.html +++ b/fetchmail-FAQ.html @@ -1,1515 +1,1810 @@ - - -
-Back to Fetchmail Home Page - | To Site Map - | $Date: 2002/02/01 02:14:23 $
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- Frequently Asked Questions About Fetchmail-Before reporting any bug, please read G3 for advice -on how to include diagnostic information that will get your bug fixed -as quickly as possible. + + Frequently Asked Questions About Fetchmail+ +Support? Bug reports? Please read G3 for what information is required to get your problem +solved as quickly as possible. + +Note that this FAQ is occasionally updated from the Git repository +and speaks in the past tense ("since") about a fetchmail release that is +not yet available. Please try a release candidate for that version in +case you need the new option. If you have a question or answer you think ought to be added to -this FAQ list, mail it to fetchmail's maintainer, Eric S. Raymond, at -esr@thyrsus.com. - - General questions:- -G1. What is fetchmail and why should I bother?-G2. Where do I find the latest FAQ and fetchmail sources? -G3. I think I've found a bug. Will you fix it? -G4. I have this idea for a neat feature. Will you add it? -G5. Is there a mailing list for exchanging tips? -G6. So, what's this I hear about a fetchmail paper? -G7. What is the best server to use with fetchmail? -G8. What is the best mail program to use with fetchmail? -G9. How can I avoid sending my password en clair? -G10. Is any special configuration needed to use a dynamic -IP address? -G11. Is any special configuration needed to use firewalls? -G12. Is any special configuration needed to send mail? -G13. Is fetchmail Y2K-compliant? -G14. Is there a way in fetchmail to support disconnected IMAP mode? -G15. How will fetchmail perform under heavy loads? - - Build-time problems:- -B1. Make coughs and dies when building on FreeBSD.-B2. Lex bombs out while building the fetchmail lexer. -B3. I get link failures when I try to build fetchmail. - - Fetchmail configuration file grammar questions:- -F1. Why does my old .fetchmailrc no longer work?-F2. The .fetchmailrc parser won't accept my all-numeric user name. -F3. The .fetchmailrc parser won't accept my host or username beginning with `no'. -F4. I'm getting a `parse error' message I don't understand. - - Configuration questions:- -C1. Why do I need a .fetchmailrc when running as root on my own machine?-C2. How can I arrange for a fetchmail daemon to get killed when I log out? -C3. How do I know what interface and address to use with --interface? -C4. How can I set up support for sendmail's anti-spam features? -C5. How can I poll some of my mailboxes more/less often than others? -C6. Fetchmail works OK started up manually, but not from an init script. -C7. How can I forward mail to another host?. - - How to make fetchmail play nice with various MTAs:- -T1. How can I use fetchmail with sendmail?-T2. How can I use fetchmail with qmail? -T3. How can I use fetchmail with exim? -T4. How can I use fetchmail with smail? -T5. How can I use fetchmail with SCO's MMDF? -T6. How can I use fetchmail with Lotus Notes? - - How to make fetchmail work with various servers:- -S1. How can I use fetchmail with qpopper?-S2. How can I use fetchmail with Microsoft Exchange? -S3. How can I use fetchmail with Compuserve RPA? -S4. How can I use fetchmail with Demon Internet's SDPS? -S5. How can I use fetchmail with usa.net's servers? -S6. How can I use fetchmail with HP OpenMail? -S7. How can I use fetchmail with geocities POP3 servers? -S8. How can I use fetchmail with Hotmail? -S9. How can I use fetchmail with MSN? -S10. How can I use fetchmail with SpryNet? -S11. How can I use fetchmail with FTGate? -S12. How can I use fetchmail with MailMax? -S13. How can I use fetchmail with Novell GroupWise? -S14. How can I use fetchmail with InterChange? - - How to set up well-known security and authentication methods:- -K1. How can I use fetchmail with SOCKS?-K2. How can I use fetchmail with IPv6 and IPsec? -K3. How can I get fetchmail to work with ssh? -K4. What do I have to do to use the IMAP-GSS protocol? -K5. How can I use fetchmail with SSL? - - Runtime fatal errors:- -R1. Fetchmail isn't working, and -v shows `SMTP connect failed' messages.-R2. When I try to configure an MDA, fetchmail doesn't work. -R3. Fetchmail dumps core when given an invalid rc file. -R4. Fetchmail dumps core in -V mode, but operates normally otherwise. -R5. Running fetchmail in daemon mode doesn't work. -R6. Fetchmail randomly dies with socket errors. -R7. Fetchmail running as root stopped working after an OS upgrade +this FAQ list, file it to one of the trackers at our BerliOS + project site or post to one of the fetchmail mailing lists (see +below). + + Contents+ +Detailed Contents+G. General problems +B. Build-time problems +F. Fetchmail configuration file grammar questions +C. Configuration questions +T. How to make fetchmail play nice with various MTAs +S. How to make fetchmail work with various servers +I. How to fetchmail work with specific ISPs +K. How to set up well-known security and authentication +R. Runtime fatal errors +H. Hangs and lockups +D. Disappearing mail +M. Multidrop-mode problems +X. Mangled mail +O. Other problems + + Detailed Contents+ +General problems+ +G1. What is fetchmail and why should I bother?+G2. Where do I find the latest FAQ and fetchmail sources? +G3. Something doesn't work/I think I've found a bug. Will you fix it? +G4. I have this idea for a neat feature. Will you add it? +G5. I want to make fetchmail remove kept mail after some days. +G6. Is there a mailing list for exchanging tips? +G7. So, what's this I hear about a fetchmail paper? +G8. What is the best server to use with fetchmail? +G9. What is the best mail program to use with fetchmail? +G10. How can I avoid sending my password en clair? +G11. Is any special configuration needed to use a dynamic IP address? +G12. Is any special configuration needed to use firewalls? +G13. Is any special configuration needed to send mail? +G14. Is fetchmail Y2K-compliant? +G15. Is there a way in fetchmail to support disconnected IMAP mode? +G16. How will fetchmail perform under heavy loads? + + + Build-time problems+ ++B2. Lex bombs out while building the fetchmail lexer. +B3. I get link failures when I try to build fetchmail. +B4. I get build failures in the intl directory. + + Fetchmail configuration file grammar questions+ +F1. Why does my old .fetchmailrc no longer work?+F2. The .fetchmailrc parser won't accept my all-numeric user name. +F3. The .fetchmailrc parser won't accept my host or username beginning with 'no'. +F4. I'm getting a 'parse error' message I don't understand. + + Configuration questions+ +C1. Why do I need a .fetchmailrc when running as root +on my own machine?+C2. How can I arrange for a fetchmail daemon to get +killed when I log out? +C3. How do I know what interface and address to use +with --interface? +C4. How can I set up support for sendmail's anti-spam +features? +C5. How can I poll some of my mailboxes more/less +often than others? +C6. Fetchmail works OK started up manually, but not +from an init script. +C7. How can I forward mail to another +host? +C8. Why is "NOMAIL" an error?/I frequently get messages +from cron! + + How to make fetchmail play nice with various MTAs+ +T1. How can I use fetchmail with sendmail?+T2. How can I use fetchmail with qmail? +T3. How can I use fetchmail with exim? +T4. How can I use fetchmail with smail? +T5. How can I use fetchmail with SCO's MMDF? +T6. How can I use fetchmail with Lotus Notes? +T7. How can I use fetchmail with Courier IMAP? +T8. How can I use fetchmail with vbmailshield? + + How to make fetchmail work with various servers+ ++S2. How can I use fetchmail with Microsoft Exchange? +S3. How can I use fetchmail with HP OpenMail? +S4. How can I use fetchmail with Novell GroupWise? +S5. How can I use fetchmail with InterChange? +S6. How can I use fetchmail with MailMax? +S7. How can I use fetchmail with FTGate? + + How to fetchmail work with specific ISPs+ +I1. How can I use fetchmail with Compuserve RPA?+I2. How can I use fetchmail with Demon Internet's SDPS? +I3. How can I use fetchmail with usa.net's servers? +I4. How can I use fetchmail with geocities POP3 servers? +I5. How can I use fetchmail with Hotmail or Lycos Webmail? +I6. How can I use fetchmail with MSN? +I7. How can I use fetchmail with SpryNet? +I8. How can I use fetchmail with comcast.net or other + Maillennium servers? +I9. How can I use fetchmail with GMail/Google Mail? + + How to set up well-known security and authentication +methods+ +K1. How can I use fetchmail with SOCKS?+K2. How can I use fetchmail with IPv6 and IPsec? +K3. How can I get fetchmail to work with ssh? +K4. What do I have to do to use the IMAP-GSS protocol? +K5. How can I use fetchmail with SSL? +K6. How can I tell fetchmail not to try TLS if the server + advertises it? Why does fetchmail use SSL even though not configured? + + Runtime fatal errors+ +R1. Fetchmail isn't working, and -v shows 'SMTP +connect failed' messages.+R2. When I try to configure an MDA, fetchmail doesn't +work. +R3. Fetchmail dumps core when given an invalid rc +file. + +R5. Running fetchmail in daemon mode doesn't +work. +R6. Fetchmail randomly dies with socket errors. +R7. Fetchmail running as root stopped working after +an OS upgrade R8. Fetchmail is timing out after fetching certain -messages but before deleting them -R9. Fetchmail is timing out during message fetches -R10. Fetchmail is dying with SIGPIPE. - - Hangs and lockups:- -H1. Fetchmail hangs when used with pppd.-H2. Fetchmail hangs during the MAIL FROM exchange. -H3. Fetchmail hangs while fetching mail. - - Disappearing mail:- -D1. I think I've set up fetchmail correctly, but I'm not getting any mail.-D2. All my mail seems to disappear after a dropped connection. -D3. Mail that was being fetched when I interrupted my fetchmail seems to have been vanished. - - Multidrop-mode problems:- -M1. I've declared local names, but all my multidrop mail is going to root anyway.-M2. I can't seem to get fetchmail to route to a local domain properly. -M3. I tried to run a mailing list using multidrop, and I have a mail loop! -M4. My multidrop fetchmail seems to be having DNS problems. -M5. I'm seeing long DNS delays before each message is processed. -M6. How do I get multidrop mode to work with majordomo? -M7. Multidrop mode isn't parsing envelope addresses from -my Received headers as it should. -M8. Users are getting multiple copies of messages. - - Mangled mail:- -X1. Spurious blank lines are appearing in the headers of fetched mail.-X2. My mail client can't see a Subject line. -X3. Messages containing "From" at start of line are being split. -X4. My mail is being mangled in a new and different way. -X5. Using POP3, retrievals seems to be fetching too much! -X6. My mail attachments are being dropped or mangled. -X7. Some mail attachments are hanging fetchmail. -X8. A spurious ) is being appended to my messages. - - Other problems:- -O1. The --logfile option doesn't work if the logfile doesn't exist.-O2. Every time I get a POP or IMAP message the header is -dumped to all my terminal sessions. -O3. Does fetchmail reread its rc file every poll cycle? +messages but before deleting them +R9. Fetchmail is timing out during message fetches + +R11. My server is hanging or emitting errors on CAPA. +R12. Fetchmail isn't working and reports getaddrinfo + errors. +R13. What does "Interrupted system call" mean? +R14. Since upgrading fetchmail/OpenSSL, I can no longer connect! +R15. Help, I'm getting Authorization failure! + + Hangs and lockups+ +H1. Fetchmail hangs when used with pppd.+H2. Fetchmail hangs during the MAIL FROM +exchange. +H3. Fetchmail hangs while fetching mail. + + + Disappearing mail+ +D1. I think I've set up fetchmail correctly, but I'm +not getting any mail.+D2. All my mail seems to disappear after a dropped +connection. +D3. Mail that was being fetched when I interrupted my +fetchmail seems to have been vanished. + + + Multidrop-mode problems+ +M1. I've declared local names, but all my multidrop +mail is going to root anyway.+M2. I can't seem to get fetchmail to route to a local +domain properly. +M3. I tried to run a mailing list using multidrop, +and I have a mail loop! + +M5. I'm seeing long DNS delays before each message is +processed. +M6. How do I get multidrop mode to work with +majordomo? +M7. Multidrop mode isn't parsing envelope addresses +from my Received headers as it should. +M8. Users are getting multiple copies of +messages. + + + Mangled mail+ +X1. Spurious blank lines are appearing in the headers +of fetched mail.+X2. My mail client can't see a Subject +line. +X3. Messages containing "From" at start of line are +being split. +X4. My mail is being mangled in a new and different +way. + +X6. My mail attachments are being dropped or +mangled. +X7. Some mail attachments are hanging +fetchmail. +X8. A spurious ) is being appended to my +messages. +X9. Missing "Content-Transfer-Encoding" header +with Domino IMAP +X10. Fetchmail delivers partial messages + + + Other problems+ +O1. The --logfile option doesn't work if the logfile +doesn't exist.+O2. Every time I get a POP or IMAP message the header +is dumped to all my terminal sessions. +O3. Does fetchmail reread its rc file every poll +cycle? O4. Why do deleted messages show up again when I take -a line hit while downloading? -O5. Why is fetched mail being logged with my name, not the real From address? -O6. I'm seeing long sendmail delays or hangs near the start of each poll cycle. -O7. Why doesn't fetchmail deliver mail in date-sorted order? -O8. I'm using pppd. Why isn't my monitor option working? -O9. Why does fetchmail keep retrieving the same messages -over and over? -O10. Why is the received date on all my messages the same? - - Answers:-- G1. What is fetchmail and why should I bother?- -Fetchmail is a one-stop solution to the remote mail retrieval problem
-for Unix machines, quite useful to anyone with an intermittent PPP or
-SLIP connection to a remote mailserver. It can collect mail using any
-variant of POP or IMAP and forwards via port 25 to the local SMTP
-listener, enabling all the normal forwarding/filtering/aliasing
-mechanisms that would apply to local mail or mail arriving via a
-full-time TCP/IP connection.
+a line hit while downloading? + General problems+G1. What is fetchmail and why should I +bother?+ +Fetchmail is a one-stop solution to the remote mail retrieval +problem for Unix machines, quite useful to anyone with an +intermittent or dynamic-IP connection to a remote mailserver, SLIP or +PPP dialup, or leased line when SMTP isn't desired. Fetchmail can +collect mail using any variant of POP or IMAP and forwards to a the +local SMTP (via TCP socket) or LMTP (via TCP or Unix socket) listener or +into an MDA program, enabling all the normal +forwarding/filtering/aliasing mechanisms that would apply to local mail +or mail arriving via a full-time TCP/IP connection. Fetchmail is not a toy or a coder's learning exercise, but an industrial-strength tool capable of transparently handling every -retrieval demand from those of a simple single-user ISP connection up -to mail retrieval and rerouting for an entire client domain. +retrieval demand from those of a simple single-user ISP connection +up to mail retrieval and rerouting for an entire client domain. Fetchmail is easy to configure, unobtrusive in operation, powerful, -feature-rich, and well documented. +feature-rich, and well documented. + +Fetchmail is Open Source +Software. The openness of the sources enables you to review and +customize the code, and contribute your changes. -Fetchmail is open-source -software. The openness of the sources is the strongest assurance of -quality you can have. Extensive peer review by a large, -multi-platform user community has shown that fetchmail is as near -bulletproof as the underlying protocols permit. + A former fetchmail maintainer once claimed that Open Source software +were the strongest quality assurance, but the current maintainers do not +believe that open source alone is a criterion for quality – the remotely exploitable POP3 + vulnerability (CVE-2005-2335) lingered undiscovered in +fetchmail's code for years, which is a hint that open source code does +not audit itself. Fetchmail is licensed under the GNU General Public -License. +href="http://www.gnu.org/licenses/old-licenses/gpl-2.0.html">GNU General Public +License v2. Details, including an exception that allows linking +against OpenSSL, are in the COPYING file in the fetchmail +distribution. -If you found this FAQ in the distribution, see the README for fetchmail's -full feature list. + If you found this FAQ in the distribution, see the README for +fetchmail's full feature list. -- G2. Where do I find the latest FAQ and fetchmail -sources?+G2. Where do I find the latest FAQ and +fetchmail sources?The latest HTML FAQ is available alongside the latest fetchmail -sources at the fetchmail home page: - -http://www.tuxedo.org/~esr/fetchmail. You can also usually find -both in the POP -mail tools directory on Sunsite. +sources at the fetchmail home page: http://www.fetchmail.info/. +You can also usually find both in the +POP mail tools directory on iBiblio. A text dump of this FAQ is included in the fetchmail -distribution. Because it freezes at distribution release time, it may -not be completely current. +distribution. Because it freezes at distribution release time, it +may not be completely current. -- G3. I think I've found a bug. Will you fix it?+G3. Something does not work/I think I've found a bug. Will you fix it?-Yes I will, provided you include enough diagnostic information for me -to go on. Send bugs to fetchmail-friends. When reporting -bugs, please include the following: + The first thing you should to is to upgrade to the newest version of +fetchmail, and then see if the problem reproduces. So you'll probably +save us both time if you upgrade and test with the latest + version before sending in a bug report. -
Bugs will be fixed, provided you include enough diagnostic information +for me to go on. Send bugs to fetchmail-users. +When sending bugs or asking for help, please do not make up + information except your password and please +report the following: -If you have FTP access to your remote mail account, and you have any -suspicion that the bug was triggered by a particular message, please -include a copy of the message that triggered the bug. - - Often, the first thing I will do when you report a bug is tell you to -upgrade to the newest version of fetchmail, and then see if the -problem reproduces. So you'll probably save us both time if you -upgrade and test with the latest version before sending in a -bug report. - - If your bug is something that used to work but stopped working when -you upgraded, then you can help pin the bug down by trying intermediate versions of -fetchmail until you identify the revision that broke your -feature. The smart way to do this is by binary search on the version -sequence. First, try the version halfway between your last good one -and the current one. If it works, the failure was introduced in the -upper half of the sequence; if it doesn't, the failure was introduced -in the lower half. Now bisect that half in the same way. In a very -few tries, you should be able to identify the exact adjacent pair -of versions between which your bug was introduced -- and with -information like that, I can usually come up with a fix very quickly. - - Another useful thing you can do, if you're using POP3, is to test for -IMAP4 support on your mailserver using the autoprobe function of -fetchmailconf. If you have IMAP4, and fetchmailconf doesn't tell you -it's broken, switch immediately. POP3 is a weak, poorly-designed -protocol with chronic problems, and the later versions after RFC1725 -actually get worse rather than better. Changing over to IMAP4 may well -make your problem go away -- and if your ISP doesn't have IMAP4 -support, bug them to supply it. - - It is helpful if you include your .fetchmailrc file, but not necessary -unless your symptom seems to involve an error in configuration -parsing. If you do send in your .fetchmailrc, mask the passwords -first! - - If fetchmail seems to run and fetch mail, but the headers look mangled -(that is, headers are missing or blank lines are inserted in the -headers) then read the FAQ items in section X -before submitting a bug report. Pay special attention to the item on -diagnosing mail mangling. There are -lots of ways for other programs in the mail chain to screw up that -look like fetchmail's fault, but you may be able to fix these by -tweaking your configuration. - - A transcript of the failed session with -v -v (yes, that's -two -v options, enabling debug mode) will almost always be useful. -It is very important that the transcript include your POP/IMAP server's -greeting line, so I can identify it in case of server problems. This -transcript will not reveal your passwords, which are specially masked -out precisely so the transcript can be passed around. - - If you upgraded your fetchmail and something broke, you should include -session transcripts with -v -v of both the working and failing -versions. Very often, the source of the problem can instantly -identified by looking at the differences in protocol transactions. - - If the bug involves a core dump or hang, a gdb stack trace is good to have. -(Bear in mind that you can attach gdb to a running but hung process by -giving the process ID as a second argument.) You will need to -reconfigure with: - - -CFLAGS=-g LDFLAGS=" " ./configure -- -and then rebuild in order to generate a version that can be gdb-traced. +
Best of all is a mail file which, when fetched, will reproduce the -bug under the latest (current) version. + Any bug I can reproduce will usually get fixed very quickly, often -within 48 hours. Bugs I can't reproduce are a crapshoot. If the -solution isn't obvious when I first look, it may evade me for a long -time (or to put it another way, fetchmail is well enough tested that the -easy bugs have long since been found). So if you want your bug fixed -rapidly, it is not just sufficient but nearly necessary that -you give me a way to reproduce it. + - G4. I have this idea for a neat feature. Will you add it?+You can do spam filtering better with procmail or maildrop on the
-server side and (if you're the server sysadmin) sendmail.cf domain
-exclusions. You can do other policy things better with the
- I'm not going to do these; fetchmail's job is transport, not policy, and I -refuse to change it from doing one thing well to attempting many things badly. -One of my objectives is to keep fetchmail simple so it stays reliable. + If you have FTP access to your remote mail account, and you have +any suspicion that the bug was triggered by a particular message, +please include a copy of the message that triggered the bug. + +If your bug is something that used to work but stopped working +when you upgraded, then you can help pin the bug down by trying intermediate versions +of fetchmail until you identify the revision that broke your +feature. The smart way to do this is by binary search on the +version sequence. First, try the version halfway between your last +good one and the current one. If it works, the failure was +introduced in the upper half of the sequence; if it doesn't, the +failure was introduced in the lower half. Now bisect that half in +the same way. In a very few tries, you should be able to identify +the exact adjacent pair of versions between which your bug was +introduced. Please include session transcripts (as +described in the last bullet point above) of both +the working and failing versions. Often, the source of the problem +can instantly identified by looking at the differences in protocol +transactions. + +It may helpful if you include your .fetchmailrc file, but not +necessary unless your symptom seems to involve an error in +configuration parsing. If you do send in your .fetchmailrc, mask +the passwords first! Otherwise, fetchmail -V – as directed above +– will usually suffice. + +If fetchmail seems to run and fetch mail, but the headers look +mangled (that is, headers are missing or blank lines are inserted +in the headers) then read the FAQ items in section X before submitting a bug report. Pay special +attention to the item on diagnosing +mail mangling. There are lots of ways for other programs in the +mail chain to screw up that look like fetchmail's fault, but you +may be able to fix these by tweaking your configuration. + +If the bug involves a core dump or hang, a gdb stack trace is +good to have. (Bear in mind that you can attach gdb to a running +but hung process by giving the process ID as a second argument.) +You will need to reconfigure with: -For reasons fetchmail doesn't have other commonly-requested features -(such as password encryption, or multiple concurrent polls from the -same instance of fetchmail) see the design notes. + +CFLAGS=-g LDFLAGS=" " ./configure +- Fetchmail is a mature project, no longer in constant active -development. It is no longer my top project, and I am going to be -quite reluctant to add features that might either jeopardize its -stability or involve me in large amounts of coding. + Then rebuild in order to generate a version that can be +traced with a debugger such as gdb, dbx or idb. -All that said, if you have a feature idea that really is about a transport -problem that can't be handled anywhere but fetchmail, lay it on me. I'm -very accommodating about good ideas. + Best of all is a mail file which, when fetched, will reproduce +the bug under the latest (current) version. -- G5. Is there a mailing list for exchanging tips?+Any bug I can reproduce will usually get fixed quite quickly. +Bugs I can't reproduce are a crapshoot. If the solution isn't obvious +when I first look, it may evade me for a long time (or to put it another +way, fetchmail is well enough tested that the easy bugs have long since +been found). So if you want your bug fixed rapidly, it is not just +sufficient but necessary that you give me a way to +easily reproduce it. -There is a fetchmail-friends list for people who want to discuss fixes -and improvements in fetchmail and help co-develop it. It's a MailMan -list, which you can sign up for at fetchmail-friends@lists.ccil.org. -There is also an announcements-only list, fetchmail-announce@lists.ccil.org. + G4. I have this idea for a neat feature. +Will you add it?-- G6. So, what's this I hear about a fetchmail paper?+If it's reasonable for fetchmail and cannot be solved with reasonable +effort outside of fetchmail, perhaps. -The fetchmail development was also a sociological experiment, an -extended test to see if my theory about the critical features of the -Linux development model is correct. + You can do spam filtering better with procmail or maildrop on
+the server side and (if you're the server sysadmin) sendmail.cf
+domain exclusions. If you really want fetchmail to do it from the
+client side, use a The experiment was a success. I wrote a paper about it titled The
+ You can do other policy things better with the
+ fetchmail's first job is transport though, and it should do this
+well. If a feature would cause fetchmail to deteriorate in other
+respects, the feature will probably not be added. For reasons fetchmail doesn't have other commonly-requested
+features (such as password encryption, or multiple concurrent polls
+from the same instance of fetchmail) see ESR's design
+notes. Note that this document is partially obsoleted by the
+updated design notes. The second-most-requested feature for fetchmail, after
+content-based filtering, is the ability to have it remove messages
+from a maildrop after N days, typically to be used with the
+ This feature is not yet implemented. It may be at a future date,
+spare time of developers permitting. For the time being, the contrib/ directory contains some unsupported
+ tools that may help, namely mold-remover.py and delete-later. There is a fetchmail-users list
+<fetchmail-users@lists.berlios.de>
+for bug reports and people who want to discuss configuration issues of
+fetchmail. Please see G3 above for information you need to
+report. It's a Mailman list, see http://lists.berlios.de/mailman/listinfo/fetchmail-users
+for info and subscription. There is a fetchmail-devel list
+<fetchmail-devel@lists.berlios.de> for people who want to discuss
+fixes and improvements in fetchmail and help co-develop it. It's a
+Mailman list, which you can sign up for at http://lists.berlios.de/mailman/listinfo/fetchmail-devel. There is also an announcements-only list,
+<fetchmail-announce@lists.berlios.de>, which you can sign up for at http://lists.berlios.de/mailman/listinfo/fetchmail-announce. Eric S. Raymond also considered fetchmail development a sociological
+experiment, an extended test to see if my theory about the critical
+features of the Linux development model is correct. He considers the experiment a success. He wrote a paper about it titled The
Cathedral and the Bazaar which was first presented at Linux
Kongress '97 in Bavaria and very well received there. It was also
given at Atlanta Linux Expo, Linux Pro '97 in Warsaw, and the first
Perl Conference, at UniForum '98, and was the basis of an invited
-presentation at Usenix '98. The folks at Netscape tell me it helped
+presentation at Usenix '98. The folks at Netscape told ESR it helped
them decide to give
-away the source for Netscape Communicator.
-
- If you're reading a non-HTML dump of this FAQ, you can find the paper
-on the Web with a search for that title.
-
- The short answer: IMAP 2000 running over Unix.
-
- Here's a longer answer:
-
- Fetchmail will work with any POP, IMAP, ETRN, or ODMR server that
-conforms to the relevant RFCs (and even some outright broken ones like
-Microsoft Exchange and Novell
-GroupWise). This doesn't mean it works equally well with all,
-however. POP2 servers, and POP3 servers without LAST, limit
-fetchmail's capabilities in various ways described on the manual
-page.
-
- Most modern Unixes (and effectively all Linux/*BSD systems) come with
-POP3 support preconfigured (but beware of the horribly broken POP3
-server mentioned in D2). An increasing minority
-also feature IMAP (you can detect IMAP support by running fetchmail in
-AUTO mode, or by using the `Probe for supported protocols' function in
-the fetchmailconf utility).
-
- If you have the option, we recommend using or installing an IMAP4rev1
-server; it has the best facilities for tracking message `seen' states.
-It also recovers from interrupted connections more gracefully than
-POP3, and enables some significant performance optimizations. The new
-IMAP 2000
-is particularly nice, as it supports CRAM-MD5 so you don't have to
-ship your mail password over the net en clair (fetchmail autodetects
-this capability). Older versions had support for GSSAPI giving a
-similar effect, .
-
- Don't be fooled by NT/Exchange propaganda. M$ Exchange is just plain
-broken (see item S2) and NT cannot handle the
-sustained load of a high-volume remote mail server. Even Microsoft
-itself knows better than to try this; their own Hotmail service runs
-over Solaris! For extended discussion, see John Kirch's excellent white paper on Unix
-vs. NT performance.
-
- Source for a high-quality supported implementation of POP is available
-from the Eudora
-FTP site. Don't use 2.5, which has a rather restrictive license.
-The 2.5.2 version appears to restore the open-source license of
-previous versions.
-
- Fetchmail will work with all popular mail transport
-programs. It also doesn't care which user agent you use, and user
-agents are as a rule almost equally indifferent to how mail is
-delivered into your system mailbox. So any of the popular Unix mail
-agents -- elm, give
+away the source for Netscape Communicator. If you're reading a non-HTML dump of this FAQ, you can find the
+paper on the Web with a search for that title. Fetchmail will work with any POP, IMAP, ETRN, or ODMR server
+that conforms to the relevant standards/RFCs (and even some outright
+broken ones like Microsoft Exchange and Novell GroupWise). This doesn't mean it works equally
+well with all, however. POP2 servers, and POP3 servers without UIDL,
+limit fetchmail's capabilities in various ways described on the manual
+page. Most modern Unixes (and effectively all Linux/*BSD systems) come
+with POP3 support preconfigured (but beware of the horribly broken
+POP3 server mentioned in D2). An increasing
+minority also feature IMAP (you can detect IMAP support by using the
+'Probe for supported protocols' function in the fetchmailconf
+utility - unfortunately it does not detect SSL-wrapped variants). If you have the option, we recommend using or installing an
+IMAP4rev1 or UIDL-capable POP3 server. A decent POP3/IMAP server that has recently become popular is Dovecot. Avoid qmail,
+ it's broken and unmaintained. Fetchmail will work with all popular mail
+transport programs. It also doesn't care which user agent you
+use, and user agents are as a rule almost equally indifferent to
+how mail is delivered into your system mailbox. So any of the
+popular Unix mail agents – elm, pine, mh, or mutt -- will work fine with fetchmail.
+href="http://www.cs.indiana.edu/docproject/mail/mh.html">mh All this having been said, I can't resist putting in a discreet plug -for mutt. My own personal mail -setup is sendmail plus fetchmail plus mutt. Mutt's interface is only -a little different from that of its now-moribund ancestor elm, but its -excellent handling of MIME and PGP put it in a class by itself. You -won't need its built-in POP3 support, though; most of the mutt -developers will cheerfully admit that fetchmail's is better :-). + All this having been said, I can't resist putting in a discreet +plug for mutt. Mutt's interface +is only a little different from that of its now-moribund ancestor +elm, but its flexibility and excellent handling of MIME and PGP put it +in a class by itself. You won't need its built-in POP3 support, though. + -- G9. How can I avoid sending my password en clair?+G10. How can I avoid sending my password +en clair?-Depending on what your mail server you are talking to, this ranges -from trivial to impossible. It may even be next to useless. - - Most people use fetchmail over phone wires, which are hard to tap. -Anybody with the skill and resources to do this could get into your -server mailbox with much less effort by subverting the server host. -So if your provider setup is modem wires going straight into a service -box, you probably don't need to worry. + Depending on what your mail server you are talking to, this +ranges from trivial to impossible. It may even be next to +useless. In general there is little point in trying to secure your fetchmail transaction unless you trust the security of the server host you are -retrieving mail from. Your vulnerability is more likely to be an -insecure local network on the server end (e.g. to somebody with a TCP/IP -packet sniffer intercepting Ethernet traffic between the modem -concentrator you dial in to and the mailserver host). - - Having realized this, you need to ask whether password encryption -alone will really address your security exposure. If you think you -might be snooped between server and client, it's better to use -end-to-end encryption on your whole mail stream so none of it can be -read. One of the advantages of fetchmail over conventional SMTP-push -delivery is that you may be able to arrange this by using ssh(1); see -K3. - - Note that ssh is not a complete privacy solution either, as your mail -could have been snooped in transit to your POP server from wherever it -originated. For best security, agree with your correspondents to use -a tool such as GPG (Gnu Privacy -Guard) or PGP (Pretty Good Privacy). - - If ssh/sshd isn't available, or you find it too complicated for you to -set up, password encryption will at least keep a malicious cracker -from deleting your mail, and require him to either tap your connection -continuously or crack root on the server in order to read it. +retrieving mail from. Your vulnerability is more likely to be an +insecure local network on the server end (e.g. to somebody with a +TCP/IP packet sniffer intercepting Ethernet traffic between the modem +concentrator or DSL POP you dial in to and the mailserver host). + +Having realized this, you need to ask whether password +encryption alone will really address your security exposure. If you +think you might be snooped between server and client, it's better +to use end-to-end encryption such as GnuPG (see below) on your whole +mail stream so none of it can be read. One of the advantages of +fetchmail over conventional SMTP-push delivery is that you may be able +to arrange encryption by using ssh(1); see K3. + +Note that ssh is not a complete privacy solution either, as your +mail could have been snooped in transit to your POP server from +wherever it originated. For best security, agree with your +correspondents to use a tool such as GnuPG (Gnu Privacy Guard) or PGP +(Pretty Good Privacy). + +If ssh/sshd isn't available, or you find it too complicated for +you to set up, password encryption will at least keep a malicious +cracker from deleting your mail, and require him to either tap your +connection continuously or crack root on the server in order to +read it. You can deduce what encryptions your mail server has available
-by looking at the server greeting line (and, for IMAP, the
-response to a CAPABILITY query). Do a If your mailserver is using IMAP 2000, you'll have CRAM-MD5 support -built in. Fetchmail autodetects this; you can skip the rest of this -section. - - The POP3 facility you are most likely to have available is APOP. This is a
-POP3 feature supported by many servers (fetchmailconf's autoprobe
-facility will detect it and tell you if you have it). If you see
-something in the greeting line that looks like an
-angle-bracket-enclosed Internet address with a numeric left-hand part,
-that's an APOP challenge (it will vary each time you log in). You can
-register a secret on the host (using Alternatively, you may have Kerberos available. This may require you -to set up some magic files in your home directory on your client -machine, but means you can omit specifying any password at all. - - Fetchmail supports two different Kerberos schemes. One is a POP3 -variant called KPOP; consult the documentation of your mail server to -see if you have it (one clue is the string "krb-IV" in the greeting -line on port 110). The other is an IMAP and POP3 facility described -by RFC1731 and RFC1734. You can tell if this one is present by looking -for AUTH=KERBEROS_V4 in the CAPABILITY response. - - If you are fetching mail from a CompuServe POP3 account, you can use -their RPA authentication (which works much like APOP). See S3 for details. If you are fetching mail from -Microsoft Exchange using IMAP, you will be able to use NTLM. - - Your POP3 server may have the RFC1938 OTP capability to use one-time -passwords (if it doesn't, you can get OTP patches for the 2.2 version -of the Qualcomm popper from Craig Metz). To check -this, look for the string "otp-" in the greeting line. If you see it, -and your fetchmail was built with OPIE support compiled in (see the -distribution INSTALL file), fetchmail will detect it also. When using -OTP, you will specify a password but it will not be sent en clair. - - You can get both POP3 and IMAP OTP patches from Craig -Metz at http://www.inner.net/pub/.
-These patches use a SASL authentication method named "X-OTP" because
-there is not currently a standard way to do this; fetchmail also uses
-this method, so the two will interoperate happily. They better,
-because this is how Craig gets his mail ;-)
+by looking at the server greeting line (and, for IMAP, the response
+to a CAPABILITY query). Do a If your mailserver is using IMAP 2000, it'll have CRAM-MD5 +support built in. Fetchmail autodetects this; you can skip the rest +of this section. + +The POP3 facility you are most likely to have available is APOP.
+This is a POP3 feature supported by many servers (fetchmailconf's
+autoprobe facility will detect it and tell you if you have it). If
+you see something in the greeting line that looks like an
+angle-bracket-enclosed Internet address with a numeric left-hand
+part, that's an APOP challenge (it will vary each time you log in).
+For some hosts, you need to register a secret on the host (using
+ Alternatively, you may have Kerberos available. This may require +you to set up some magic files in your home directory on your +client machine, but means you can omit specifying any password at +all. + +Fetchmail supports two different Kerberos schemes. One is a POP3 +variant called KPOP; consult the documentation of your mail server +to see if you have it (one clue is the string "krb-IV" in the +greeting line on port 110). The other is an IMAP and POP3 facility +described by RFC1731 and RFC1734. You can tell if this one is +present by looking for AUTH=KERBEROS_V4 in the CAPABILITY +response. + +If you are fetching mail from a CompuServe POP3 account, you can +use their RPA authentication. See I1 for details. +If you are fetching mail from +Microsoft Exchange using IMAP, you will be able to use NTLM. + +Your POP3 server may have the RFC1938 OTP capability to use +one-time passwords (if it doesn't, you can get OTP patches for the +2.2 version of the Qualcomm popper from Craig +Metz). To check this, look for the string "otp-" in the +greeting line. If you see it, and your fetchmail was built with +OPIE support compiled in (see the distribution INSTALL file), +fetchmail will detect it also. When using OTP, you will specify a +password but it will not be sent en clair. + +You can get both POP3 and IMAP OTP patches from Craig Metz at http://www.inner.net/opie. + +These patches use a SASL authentication method named "X-OTP" +because there is not currently a standard way to do this; fetchmail +also uses this method, so the two will interoperate happily. They +better, because this is how Craig gets his mail ;-) Finally, you can use SSL for complete -end-to-end encryption if you have an SSL-enabled mailserver. +end-to-end encryption if you have an SSL-enabled mailserver. -- G10. Is any special configuration needed to use a dynamic IP address?+G11. Is any special configuration needed +to use a dynamic IP address?Yes. In order to avoid giving indigestion to certain picky MTAs -(notably exim), fetchmail always makes the RCPT TO -address it feeds the MTA a fully qualified one with a hostname part. -Normally it does this by appending @ and "localhost", but when you are -using Kerberos or ETRN mode it will append @ and your machine's -fully-qualified domain name (FQDN). - - Appending the FQDN can create problems when fetchmail is running in daemon -mode and outlasts the dynamic IP address assignment your client -machine had when it started up. - - Since the new IP address (looked up at RCPT TO interpretation time) -doesn't match the original, the most benign possible result is that -your MTA thinks it's seeing a relaying attempt and refuses. More -frequently, fetchmail will try to connect to a nonexistent host -address and time out. Worst case, you could up forwarding your mail -to the wrong machine! - - Use the Only one fetchmail option interacts directly with your IP address,
-` I recommend against trying to set up the You can't use ETRN if you have a dynamic IP address (your ISP changes -your IP address occasionally, possibly with every connect). You need -to have your own registered domain and a definite IP address -registered for that domain. The server needs to be configured to -accept mail for your domain but then queue it to forward to your -machine. ETRN just tells to server to flush its queue for your -domain. Fetchmail doesn't actually get the mail in that case. - - You can use On-Demand Mail Relay (ODMR) with a dynamic IP address; -that's what it was designed for, and it provides capabilities very -similar to ETRN. Unfortunately ODMR servers are not yet widely -deployed, as of early 2001. - - If you're using a dynamic-IP configuration, one other (non-fetchmail) -problem you may run into with outgoing mail is that some sites will -bounce your email because the hostname your giving them isn't real -(and doesn't match what they get doing a reverse DNS on your -dynamically-assigned IP address). If this happens, you need to hack -your sendmail so it masquerades as your host. Setting +(notably exim), fetchmail always makes the RCPT TO +address it feeds the MTA a fully qualified one with a hostname +part. Normally it does this by appending @ and "localhost", but +when you are using Kerberos or ETRN mode it will append @ and your +machine's fully-qualified domain name (FQDN). + +Appending the FQDN can create problems when fetchmail is running +in daemon mode and outlasts the dynamic IP address assignment your +client machine had when it started up. + +Since the new IP address (looked up at RCPT TO interpretation +time) doesn't match the original, the most benign possible result +is that your MTA thinks it's seeing a relaying attempt and refuses. +More frequently, fetchmail will try to connect to a nonexistent +host address and time out. Worst case, you could up forwarding your +mail to the wrong machine! + +Use the Only one fetchmail option interacts directly with your IP
+address, ' I recommend against trying to set up the You can't use ETRN if you have a dynamic IP address (your ISP +changes your IP address occasionally, possibly with every connect). +You need to have your own registered domain and a definite IP +address registered for that domain. The server needs to be +configured to accept mail for your domain but then queue it to +forward to your machine. ETRN just tells to server to flush its +queue for your domain. Fetchmail doesn't actually get the mail in +that case. + +You can use On-Demand Mail Relay (ODMR) with a dynamic IP +address; that's what it was designed for, and it provides +capabilities very similar to ETRN. Unfortunately ODMR servers are +still not yet widely deployed, as of 2006. + +If you're using a dynamic-IP configuration, one other +(non-fetchmail) problem you may run into with outgoing mail is that +some sites will bounce your email because the hostname you're giving +them isn't real (and doesn't match what they get doing a reverse +DNS on your dynamically-assigned IP address). If this happens, you +need to hack your sendmail so it masquerades as your host. +Setting DMsmarthost.here-in your sendmail.cf will work, or you can set+ in your MASQUERADE_AS(smarthost.here)-in the m4 configuration and do a reconfigure. (In both cases, replace - smarthost.here with the actual name of your mailhost.)
-See the sendmail
-FAQ for more details.
+in the m4 configuration and do a reconfigure. (In both cases,
+replace - G11. Is any special configuration needed to use firewalls?+G12. Is any special configuration needed +to use firewalls?-No. You can use fetchmail with SOCKS, the standard tool for -indirecting TCP/IP through a firewall. You can find out about SOCKS, -and download the SOCKS software including server and client code, at -the SOCKS distribution -site. + No. You can use fetchmail with SOCKS, the standard tool for +indirecting TCP/IP through a firewall. You can find out about +SOCKS, and download the SOCKS software including server and client +code, at the SOCKS distribution +site. The specific recipe for using fetchmail with a firewall is at K1 +href="#K1">K1 -- G12. Is any special configuration needed to send mail?+G13. Is any special configuration needed +to send mail?-A user asks: but how do we send mail out to the POP3 server? Do I need -to implement another tool or will fetchmail do this too? + A user asks: but how do we send mail out to the POP3 server? Do +I need to implement another tool or will fetchmail do this too? -Fetchmail only handles the receiving side. The sendmail or other + Fetchmail only handles the receiving side. The sendmail or other preinstalled MTA on your client machine will handle sending mail automatically; it will ship mail that is submitted while the -connection is active, and put mail that is submitted while -the connection is inactive into the outgoing queue. +connection is active, and put mail that is submitted while the +connection is inactive into the outgoing queue. -Normally, sendmail is also run periodically (every 15 minutes on most -Linux systems) in a mode that tries to ship all the mail in the -outgoing queue. If you have set up something like pppd to + Normally, sendmail is also run periodically (every 15 minutes on +most Linux systems) in a mode that tries to ship all the mail in +the outgoing queue. If you have set up something like pppd to automatically dial out when your kernel is called to open a TCP/IP -connection, this will ensure that the mail gets out. +connection, this will ensure that the mail gets out. -- G13. Is fetchmail Y2K-compliant?+G14. Is fetchmail +Y2K-compliant?-Fetchmail is fully Y2K-compliant.+ Fetchmail is fully Y2K-compliant. -Fetchmail could theoretically have problems when the 32-bit time_t -counters roll over in 2038, but I doubt it. Timestamps aren't used -for anything but log entry generation. Anyway, if you aren't running -on a 64-bit machine by then, you'll deserve to lose. +Fetchmail could theoretically have problems when the 32-bit +time_t counters roll over in 2038, but I doubt it. Timestamps +aren't used for anything but log entry generation. Anyway, if you +aren't running on a 64-bit machine by then, you'll deserve to +lose. -- G14. Is there a way in fetchmail to support disconnected IMAP mode?+G15. Is there a way in fetchmail to +support disconnected IMAP mode?-No. Fetchmail is a mail transport agent, best understood as a protocol -gateway between POP3/IMAP servers and SMTP. Disconnected operation -requires an elaborate interactive client. It's a very different problem. + No. Fetchmail is a mail transport agent, best understood as a +protocol gateway between POP3/IMAP servers and SMTP. Disconnected +operation requires an elaborate interactive client. It's a very +different problem. -- G15. How will fetchmail perform under heavy loads?+G16. How will fetchmail perform under +heavy loads?Fetchmail streams message bodies line-by-line; the most core it -ever requires per message is enough memory to hold the RFC822 header, and -that storage is freed when body processing begins. It is, accordingly, -quite economical in its use of memory. +ever requires per message is enough memory to hold the RFC822 +header, and that storage is freed when body processing begins. It +is, accordingly, quite economical in its use of memory. It will store +the UID or UIDL data in core however, which can become considerable if +you are keeping lots of messages on the server. After startup time, a fetchmail running in daemon mode stats its -configuration file once per poll cycle to see whether it has changed -and should be rescanned. Other than that, a fetchmail in normal -operation doesn't touch the disk at all; that job is left up to the -MTA or MDA the fetchmail talks to. - - Fetchmail's performance is usually bottlenecked by latency on the POP -server or (less often) on the TCP/IP link to the server. This is not -a problem readily solved by tuning fetchmail, or even by buying more -TCP/IP capacity (which tends to improve bandwidth but not necessarily -latency). +configuration file once per poll cycle to see whether it has +changed and should be rescanned. Other than that, a fetchmail in +normal operation doesn't touch the disk at all; that job is left up +to the MTA or MDA the fetchmail talks to. -- B1. Make coughs and dies when building on FreeBSD.+Fetchmail's performance is usually bottlenecked by latency on +the POP server or (less often) on the TCP/IP link to the server. +This is not a problem readily solved by tuning fetchmail, or even +by buying more TCP/IP capacity (which tends to improve bandwidth +but not necessarily latency). -The vendor-supplied make on FreeBSD systems can only be used within -FreeBSD's "scope", e.g. the ports collection. Type "gmake" to run GNU -make and better things will happen. + + Build-time problems+
- |
service | port |
---|---|
IMAP | 143 |
IMAP+SSL | 993 |
POP3 | 110 |
POP3+SSL | 995 |
Non-fatal signals (such as timers set by fetchmail itself) can +interrupt long-running functions and will then be reported as +"Interrupted system call". These can sometimes be timeouts.
+ +If the upgrade you did encompassed an upgrade to OpenSSL 1.0.0 or newer, you
+may need to run c_rehash
on your certificate directories,
+particularly if you are using local certs directories (f. i. through fetchmail's --sslcertpath
option).
Reason: OpenSSL 1.0.0, relative to earlier versions, uses a different hash
+for the symbolic links (symlinks) in its certs/
directory, so you
+need to recreate the symlinks by running c_rehash
+ /etc/ssl/certs (adjust this to where your installation keeps its
+certificates), and you cannot easily share this certs directory with
+applications linked against older OpenSSL versions.
Note: OpenSSL's c_rehash
script is broken in several versions,
+which can cause malfunction if several OpenSSL tools versions are installed in
+parallel in separate directories. In such cases, you may need a workaround to
+get things going. Assuming your OpenSSL 1.0.0 is installed in
+/opt/openssl1.0.0
and your certificates are in
+/home/hans/certs
, you'd do this (the corresponding fetchmail
+option is --sslcertpath /home/hans/certs on the commandline and
+sslcertpath /home/hans/cert in the rcfile):
+env PATH=/opt/openssl1.0.0/bin /opt/openssl1.0.0/bin/c_rehash /home/hans/certs +-
Or maybe you're trying to run fetchmail in multidrop mode as root -without a .fetchmailrc file. This doesn't do what you think it -should; see question C1. +
First, try upgrading to fetchmail 6.3.18 or newer. Release 6.3.18 has +received a considerable number of bug fixes for the authentication +feature (AUTH, AUTHENTICATE, SASL). Most notably, fetchmail aborts SASL +authentication attempts properly with an asterisk if it detects that it +cannot make progress with a particular authentication scheme. This fixes +issues where GSSAPI-enabled fetchmail cannot authenticate against +Microsoft Exchange 2007 and 2010. Note that this is a +bug in old fetchmail versions!
+ +Fetchmail by default attempts to authenticate using various schemes. +Fetchmail tries these schemes in order of descending security, meaning +the most secure schemes are tried first.
+ +However, sometimes the server offers a secure authentication scheme +that is not properly configured, or an authentication scheme such as +GSSAPI that requires credentials to be acquired externally. In some +situations, fetchmail cannot know that the scheme will fail beforehand, +without trying it. In most cases, fetchmail should proceed to the next +authentication scheme automatically, but this sometimes does not +work.
+ +Solution: Configure the right authentication scheme
+explicitly, for instance, with --auth cram-md5 or --auth
+ password on the command line or auth "cram-md5"
or
+ auth "password"
in the rcfile. Details can be found
+ in the manual page.
+ Note that auth password should only be used
+ across secure links (see the sslcertck and ssl/sslproto options).
+
Your problem may be with pppd's 'demand' option. We have a +report that fetchmail doesn't play well with it, but works with +pppd if 'demand' is turned off. We have no idea why this is.
+ +The symptom: 'fetchmail -v' retrieves mail fine, but appears to +hang after sending the MAIL FROM command
-Or you may not be connecting to the SMTP listener. Run fetchmail -v -and see R1. +
+SMTP> MAIL FROM: <someone@somewhere> +-
The hang is actually occuring when sendmail looks up a sender's +address in DNS. The problem isn't in fetchmail but in the +configuration of sendmail. You must enable the 'nodns' and +'nocanonify' features of sendmail.
-One POP3 daemon used in the Berkeley Unix world that reports itself as -POP3 version 1.004 actually throws the queue away. 1.005 fixed that. -If you're running this one, upgrade immediately. (It also truncates -long lines at column 1024) +Here was my fix for RedHat 7.2:
-Many POP servers, if an interruption occurs, will restore the whole -mail queue after about 10 minutes. Others will restore it right -away. If you have an interruption and don't see it right away, cross -your fingers and wait ten minutes before retrying. +
Some servers (such as Microsoft's NTMail) are mis-designed to restore
-the entire queue, including messages you have deleted. If you have
-one of these and it flakes out on you a lot, try setting a small
---fetchlimit
value. This will result in more IP connects
-to the server, but will mean it actually executes changes to the queue
-more often.
+
Qualcomm's qpopper, used at many BSD Unix sites, is better behaved. -If its connection is dropped, it will first execute all DELE commands as -though you had issued a QUIT (this is a technical violation of -the POP3 RFCs, but a good idea in a world of flaky phone lines). Then it -will re-queue any message that was being downloaded at hangup time. -Still, qpopper may require a noticeable amount of time to do deletions -and clean up its queue. (Fetchmail waits a bit before retrying in -order to avoid a `lock busy' error.) +
+ FEATURE(nodns) + FEATURE(nocanonify) ++
However, IMAP2bis has a design problem in that its normal fetch -command marks a message `seen' as soon as the fetch command to get it -is sent down. If for some reason the message isn't actually delivered -(you take a line hit during the download, or your port 25 listener -can't find enough free disk space, or you interrupt the delivery in -mid-message) that `seen' message can lurk invisibly in your server -mailbox forever. +
+ # m4 sendmail-mine.cf > /etc/sendmail.cf ++
Workaround: add the `fetchall
' keyword to your fetch options.
+
Solution: switch to an IMAP4 server. +
For more details consult the file +/usr/share/sendmail-cf/README.
-Symptom: 'fetchmail -v' retrieves the first few messages, +but hangs returning:
-These errors usually indicate some kind of DNS configuration problem -either on the server or your client machine. +
+ fetchmail: SMTP< 550 5.0.0 Access denied + fetchmail: SMTP> RSET + fetchmail: SMTP< 250 2.0.0 Reset state + .......fetchmail: flushed + fetchmail: POP3> DELE 1 + fetchmail: POP3< +OK marked deleted +-
The easiest workaround is to add a `via
' option (if
-necessary) and add enough aka declarations to cover all of your
-mailserver's aliases, then say `no dns
'. This will take
-DNS out of the picture (though it means mail may be uncollected if
-it's sent to an alias of the mailserver that you don't have
-listed).
+
Check and see if you're allowing sendmail connections through +TCP wrappers.
-It would be better to fix your DNS, however. DNS problems can hurt -you in lots of ways, for example by making your machines -intermittently or permanently unreachable to the rest of the net. +
Adding 'sendmail : 127.0.0.1' to /etc/hosts.allow could solve +this problem.
-Occasionally these errors indicate the sort of header-parsing problem -described in M7. +
Maybe you have a .forward or alias set up that you've forgotten +about. You should probably remove it.
-A lot of people want to use fetchmail as a poor man's internetwork -mail gateway, picking up mail accumulated for a whole domain in a single -server mailbox and then routing based on what's in the To/Cc/Bcc lines. +Or maybe you're trying to run fetchmail in multidrop mode as +root without a .fetchmailrc file. This doesn't do what you think it +should; see question C1.
-In general, this is not really a good idea. It would be smarter to -just let the mail sit in the mailserver's queue and use fetchmail's -ETRN or ODMR modes to trigger SMTP sends periodically (of course, this means -you have to poll more frequently than the mailserver's expiration period). -If you can't arrange this, try setting up a UUCP feed. +
Or you may not be connecting to the SMTP listener. Run fetchmail +-v and see R1.
-If neither of these alternatives is available, multidrop mode may do
-(though you are going to get hurt by some mailing list
-software; see the caveats under THE USE AND ABUSE OF MULTIDROP
-MAILBOXES on the man page). If you want to try it, the way to do it
-is with the `localdomains
' option.
+
Or you may have your local user set incorrectly. In the +following line
-In general, if you use localdomains you need to make sure of two other -things: +
+ user 'remoteuser' there with password '*' is 'localuser' here +-
1. You've actually set up your .fetchmailrc entry to invoke multidrop mode. +
make sure that 'localuser' does exist and can receive mail.
-Many people set a `localdomains
' list and then forget
-that fetchmail wants to see more than one name (or the wildcard `*')
-in a `here
' list before it will do multidrop routing.
+
2. You may have to set `no envelope'. +
One POP3 daemon used in the Berkeley Unix world that reports +itself as POP3 version 1.004 actually throws the queue away. 1.005 +fixed that. If you're running this one, upgrade immediately. (It +also truncates long lines at column 1024.)
-Normally, multidrop mode tries to deduce an envelope address from a message -before parsing the To/Cc/Bcc lines (this enables it to avoid losing to mailing -list software that doesn't put a recipient address in the To lines). +
Many POP servers, if an interruption occurs, will restore the +whole mail queue after about 10 minutes. Better ones will restore it +right away. If you have an interruption and don't see it right +away, cross your fingers and wait ten minutes before retrying.
-Some ways of accumulating a whole domain's messages in a single server
-mailbox mean it all ends up with a single envelope address that is
-useless for rerouting purposes. You may have to set `no
-envelope
' to prevent fetchmail from being bamboozled by this.
+
Good servers are designed to restore the entire queue, including
+messages you have deleted. If you have one of these and it flakes out on
+you a lot, try setting a small --fetchlimit
value. This
+will result in more IP connects to the server, but will mean it actually
+executes changes to the queue more often.
Check also answer T1 on a reliable way to do multidrop -delivery if your ISP (or your mail redirection provider) is using qmail. +
Fetchmail only sends a delete mail request to the server when
+either (a) it gets a positive delivery acknowledgment from the SMTP
+listener, or (b) it gets one of the spam-filter errors (see the
+description of the antispam>
option) from the
+listener. No interrupt can cause it to lose mail.
However, IMAP2bis has a design problem in that its normal fetch +command marks a message 'seen' as soon as the fetch command to get +it is sent down. If for some reason the message isn't actually +delivered (you take a line hit during the download, or your port 25 +listener can't find enough free disk space, or you interrupt the +delivery in mid-message) that 'seen' message can lurk invisibly in +your server mailbox forever.
+ +Workaround: add the 'fetchall
' keyword to your
+fetch options.
Solution: switch to an IMAP4 +server.
+ +Somehow your fetchmail is never recognizing the hostname part of +recipient names it parses out of Envelope-header lines (or these are +improperly configured) as +matching a name within the designated domains. To check this, run +fetchmail in foreground with -v -v on. You will probably see a lot +of messages with the format "line rejected, %s is not an alias of +the mailserver" or "no address matches; forwarding to %s."
+ +These errors usually indicate some kind of configuration +problem.
+ +The easiest workaround is to add a 'via
' option (if
+necessary) and add enough 'aka
' declarations to cover all
+of your mailserver's aliases, then say 'no dns
'. This will
+take DNS out of the picture (though it means mail may be uncollected if
+it's sent to an alias of the mailserver that you don't have listed).
Occasionally these errors indicate the sort of header-parsing +problem described in M7.
+ +A lot of people want to use fetchmail as a poor man's +internetwork mail gateway, picking up mail accumulated for a whole +domain in a single server mailbox and then routing based on what's +in the To/Cc/Bcc lines.
+ +In general, this is not really a good idea. It would be smarter +to just let the mail sit in the mailserver's queue and use +fetchmail's ETRN or ODMR modes to trigger SMTP sends periodically +(of course, this means you have to poll more frequently than the +mailserver's expiration period). If you can't arrange this, try +setting up a UUCP feed.
+ +If neither of these alternatives is available, multidrop mode
+may do (though you are going to get hurt by some mailing
+list software; see the caveats under THE USE AND ABUSE OF MULTIDROP
+MAILBOXES on the man page, and check what is needed at Matthias
+ Andree's "Requisites for working multidrop
+ mailboxes"). If you want to try it, the way to do it is
+with the 'localdomains
' option.
In general, if you use localdomains you need to make sure of two +other things:
+ +1. You've actually set up your .fetchmailrc entry to +invoke multidrop mode.
+ +Many people set a 'localdomains
' list and then
+forget that fetchmail wants to see more than one name (or the
+wildcard '*') in a 'here
' list before it will do
+multidrop routing.
2. You may have to set 'no envelope'.
+ +Normally, multidrop mode tries to deduce an envelope address +from a message before parsing the To/Cc/Bcc lines (this enables it +to avoid losing to mailing list software that doesn't put a +recipient address in the To lines).
+ +Some ways of accumulating a whole domain's messages in a single
+server mailbox mean it all ends up with a single envelope address
+that is useless for rerouting purposes. In this particular case, sell
+your ISP a clue. If that does not work, you may have to set
+'no envelope
' to prevent fetchmail from being
+bamboozled by this, but a missing envelope makes multidrop routing
+unreliable.
Check also answer T1 on a reliable way to do +multidrop delivery if your ISP (or your mail redirection provider) +is using qmail.
+ +This isn't fetchmail's fault. Check your mailing list. If the +list expansion includes yourself or anybody else at your mailserver +(that is, not on the client side) you've created a mail loop. Just +chop the host part off any local addresses in the list.
If you use sendmail, you can check the list expansion with
-sendmail -bv
.
-
-
sendmail -bv
.
-We have one report from a Linux user (not the same one as in R1!) who solved this problem by removing the reference -to -lresolv from his link line and relinking. Apparently in some -older Linux distributions the libc5 bind library version works -better. +
As of 2.2, the configure script has been hacked so the bind library -is linked only if it is actually needed. So under Linux it won't be, -and this problem should go away. +
The answer that used to be here no longer applies to + fetchmail.
-Use the `aka
' option to pre-declare as many of your
-mailserver's DNS names as you can. When an address's host part
-matches an aka name, no DNS lookup needs to be done to check it.
+
Use the 'aka
' option to pre-declare as many of your
+mailserver's DNS names as you can. When an address's host part
+matches an aka name, no DNS lookup needs to be done to check
+it.
If you're sure you've pre-declared all of your mailserver's DNS names,
-you can use the `no dns
' option to prevent other hostname
-parts from being looked up at all.
+
If you're sure you've pre-declared all of your mailserver's DNS
+names, you can use the 'no dns
' option to prevent
+other hostname parts from being looked up at all.
Sometimes delays are unavoidable. Some SMTP listeners try to call DNS -on the From-address hostname as a way of checking that the address is valid. +
Sometimes delays are unavoidable. Some SMTP listeners try to +call DNS on the From-address hostname as a way of checking that the +address is valid.
-In order for sendmail to execute the command strings in the majordomo -alias file, it is necessary for sendmail to think that the mail it -receives via SMTP really is destined for a local user name. A normal -virtual-domain setup results in delivery to the default mailbox, -rather than expansion through majordomo. +
In order for sendmail to execute the command strings in the +majordomo alias file, it is necessary for sendmail to think that +the mail it receives via SMTP really is destined for a local user +name. A normal virtual-domain setup results in delivery to the +default mailbox, rather than expansion through majordomo.
-Michael <michael@bizsystems.com> gave us a recipe for dealing -with this case that pairs a run control file like this: +
Michael <michael@bizsystems.com> gave us a recipe for +dealing with this case that pairs a run control file like this:
poll your.pop3.server proto pop3: @@ -2347,7 +2818,7 @@ poll your.pop3.server proto pop3: password yourISPpassword fetchall-with a hack on your local sendmail.cf like this: +
with a hack on your local sendmail.cf like this:
############################################# @@ -2369,41 +2840,39 @@ R< error : $- $+ > $* $#error $@ $1 $: $2 R< $+ > $+ < @ $+ > $: $>97 $1-
This ruleset just strips virtual domain names off the addresses of incoming -mail. Your sendmail must be 8.8 or newer for this to work. Michael -says: +
This ruleset just strips virtual domain names off the addresses +of incoming mail. Your sendmail must be 8.8 or newer for this to +work. Michael says:
--I use this scheme with 2 virtual domains and the default ISP -user+domain and service about 30 mail accounts + majordomo on my -inside pop3 server with fetchmail and sendmail 8.83 -+
I use this scheme with 2 virtual domains and the +default ISP user+domain and service about 30 mail accounts + +majordomo on my inside pop3 server with fetchmail and sendmail +8.83-
It may happen that you're getting what appear to be well-formed sendmail Received headers, but fetchmail can't seem to extract an -envelope address from them. There can be a couple of reasons for -this. +envelope address from them. There can be a couple of reasons for +this.
First, fetchmail might be looking at the wrong Received header. Normally it looks only on the first one it sees, on the theory that that one was last added and is going to be the one containing your -mailserver's theory of who the message was addressed to. +mailserver's theory of who the message was addressed to.
-Some (unusual) mailserver configurations will generate extra Received
-lines which you need to skip. To arrange this, use the optional
-skip prefix argument of the `envelope' option; you may need to say
-something like `envelope 1 Received
' or `envelope 2
-Received
'.
+
Some (unusual) mailserver configurations will generate extra
+Received lines which you need to skip. To arrange this, use the
+optional skip prefix argument of the 'envelope' option; you may
+need to say something like 'envelope 1 Received
' or
+'envelope 2 Received
'.
When fetchmail parses a Received line that looks like +
When fetchmail parses a Received line that looks like
Received: from send103.yahoomail.com (send103.yahoomail.com [205.180.60.92]) @@ -2411,258 +2880,278 @@ Received: from send103.yahoomail.com (send103.yahoomail.com [205.180.60.92]) for <ksturgeon@fbceg.org>; Wed, 9 Sep 1998 17:01:59 -0700-it checks to see if `iserv.ttns.net' is a DNS alias of your mailserver -before accepting `ksturgeon@fbceg.org' as an envelope address. This -check might fail if your DNS were misconfigured, or if you were using `no dns' -and had failed to declare iserv.ttns.net as an alias of your server. +
it checks to see if 'iserv.ttns.net' is a DNS alias of your +mailserver before accepting 'ksturgeon@fbceg.org' as an envelope +address. This check might fail if your DNS were misconfigured, or +if you were using 'no dns' and had failed to declare iserv.ttns.net +as an alias of your server.
-It's a consequence of multidrop. What's happening is that you have -N users subscribed to the same list. The list software sends N -copies, not knowing they will end up in the same multidrop box. Since -they are both locally addressed to all N users, fetchmail delivers N -copies to each user. +
It's a consequence of multidrop. What's happening is that you +have N users subscribed to the same list. The list software sends N +copies, not knowing they will end up in the same multidrop box. +Since they are both locally addressed to all N users, fetchmail +delivers N copies to each user.
Fetchmail tries to eliminate adjacent duplicate messages in a -multidrop mailbox. However, this logic depends on the message-ID -being identical in both copies. It also depends on the two copies -being adjacent in the server mailbox. The former is usually the case, -but the latter condition sometimes fails in a timing-dependent way if -the server was processing multiple incoming mail streams. - -
I could eliminate this problem by keeping a list of all message-IDs -received during a poll so far and dropping any message that matches a -seen mail ID. The trouble is that this is an O(N**2) operation that -might significantly slow down the retrieval of large mail batches. - -
I could eliminate this problem by keeping a list of all +message-IDs received during a poll so far and dropping any message +that matches a seen mail ID. The trouble is that this is an O(N**2) +operation that might significantly slow down the retrieval of large +mail batches.
+ +The real solution however is to make sure that fetchmail can find the +envelope recipient properly, which will reliably prevent this message +duplication.
+ +What's probably happening is that the POP/IMAP daemon on your mailserver is inserting a non-RFC822 header (like X-POP3-Rcpt:) and something in your delivery path (most likely an old version of the -deliver program, which sendmail often calls to do local delivery) is -failing to recognize it as a header. +deliver program, which sendmail often calls to do local +delivery) is failing to recognize it as a header.
-This is not fetchmail's problem. The first thing to try is installing
-a current version of deliver. If this doesn't work, try to
-figure out which other program in your mail path is inserting the
-blank line and replace that. If you can't do either of these things,
-pick a different MDA (such as procmail) and declare it with the
-`mda
' option.
+
This is not fetchmail's problem. The first thing to try is
+installing a current version of deliver. If this doesn't
+work, try to figure out which other program in your mail path is
+inserting the blank line and replace that. If you can't do either
+of these things, pick a different MDA (such as maildrop) and
+declare it with the 'mda
' option.
First, see X1. This is quite probably the same +
First, see X1. This is quite probably the same problem (X-POP3-Rcpt header or something similar being inserted by -the server and choked on by an old version of deliver). - -
The O'Reilly sendmail book does warn that IDA sendmail doesn't process -X- headers correctly. If this is your problem, all I can suggest is -replacing IDA sendmail, because it's broken and not RFC822 conformant. - -
If you know the messages aren't split in your server mailbox, then this -is a problem with your POP/IMAP server, your client-side SMTP listener or -your local delivery agent. Fetchmail cannot split messages. - -
Some POP server daemons ignore Content-Length headers and split messages on -From lines. We have one report that the 2.1 version of the BSD popper -program (as distributed on Solaris 2.5 and elsewhere) is broken this way. - -
You can test this. Declare an mda of `cat' and send yourself one -piece of mail containing "From" at start of a line. If you see a -split message, your POP/IMAP server is at fault. Upgrade to a more -recent version. - -
Sendmail and other SMTP listeners don't split RFC822 messages either. -What's probably happening is either sendmail's local delivery agent or -your mail reader are not quite RFC822-conformant and are breaking -messages on what it thinks are Unix-style From headers. You can -figure out which by looking at your client-side mailbox with vi or -more. If the message is already split in your mailbox, your local -delivery agent is the problem. If it's not, your mailreader is the -problem. +the server and choked on by an old version of +deliver).
+ +The O'Reilly sendmail book does warn that IDA sendmail doesn't +process X- headers correctly. If this is your problem, all I can +suggest is replacing IDA sendmail, because it's broken and not +RFC822 conformant.
+ +If you know the messages aren't split in your server mailbox, +then this is a problem with your POP/IMAP server, your client-side +SMTP listener or your local delivery agent. Fetchmail cannot split +messages.
+ +Some POP server daemons ignore Content-Length headers and split +messages on From lines. We have one report that the 2.1 version of +the BSD popper program (as distributed on Solaris 2.5 and +elsewhere) is broken this way.
+ +You can test this. Declare an mda of 'cat' and send yourself one +piece of mail containing "From" at start of a line. If you see a +split message, your POP/IMAP server is at fault. Upgrade to a more +recent version.
+ +Sendmail and other SMTP listeners don't split RFC822 messages +either. What's probably happening is either sendmail's local +delivery agent or your mail reader are not quite RFC822-conformant +and are breaking messages on what it thinks are Unix-style From +headers. You can figure out which by looking at your client-side +mailbox with vi or more. If the message is already split in your +mailbox, your local delivery agent is the problem. If it's not, +your mailreader is the problem.
If you can't replace the offending program, take a look at your -sendmail.cf file. There will likely be a line something like +sendmail.cf file. There will likely be a line something like
Mlocal, P=/usr/bin/procmail, F=lsDFMShP, S=10, R=20/40, A=procmail -Y -d $u-describing your local delivery agent. Try inserting the `E' option in the -flags part (the F= string). This will make sendmail turn each dangerous -start-of-line From into a >From, preventing programs further downstream -from acting up. +
describing your local delivery agent. Try inserting the 'E' +option in the flags part (the F= string). This will make sendmail +turn each dangerous start-of-line From into a >From, preventing +programs further downstream from acting up.
-The first thing you need to do is pin down what program is doing the -mangling. We don't like getting bug reports about fetchmail that are -actually due to some other program's malfeasance, so please go through -this diagnostic sequence before sending us a complaint. +
The first thing you need to do is pin down what program is doing +the mangling. We don't like getting bug reports about fetchmail +that are actually due to some other program's malfeasance, so +please go through this diagnostic sequence before sending us a +complaint.
-There are five possible culprits to consider, listed here in the order -they pass your mail: +
There are five possible culprits to consider, listed here in the +order they pass your mail:
mda
.
+mda
.Often it happens that fetchmail itself is OK, but using it exposes -pre-existing bugs in your downstream software, or your downstream -software has a bad interaction with POP/IMAP. You need to pin down -exactly where the message is being garbled in order to deduce what is -actually going on. +
Often it happens that fetchmail itself is OK, but using it +exposes pre-existing bugs in your downstream software, or your +downstream software has a bad interaction with POP/IMAP. You need +to pin down exactly where the message is being garbled in order to +deduce what is actually going on.
-The first thing to do is send yourself a test message, and retrieve it -with a .fetchmailrc entry containing the following (or by running with -the equivalent command-line options): +
The first thing to do is send yourself a test message, and +retrieve it with a .fetchmailrc entry containing the following (or +by running with the equivalent command-line options):
mda "cat >MBOX" keep fetchall-
This will capture what fetchmail gets from the server, except for (a)
-the extra Received header line fetchmail prepends, (b) header address
-changes due to rewrite
, and (c) any end-of-line changes
-due to the forcecr
and stripcr
options.
-MBOX will in fact contain what programs downstream of fetchmail
-see.
-
-
The most common causes of mangling are bugs and misconfigurations in -those downstream programs. If MBOX looks unmangled, you will know -that is what is going on and that it is not fetchmail's problem. Take -a look at the other FAQ items in this section for possible clues about -how to fix your problem. - -
If MBOX looks mangled, the next thing to do is compare it with your
-actual server mailbox (if possible). That's why you specified
-keep
, so the server copy would not be deleted. If your
-server mailbox looks mangled, programs upstream of your server mailbox
-are at fault. Unfortunately there is probably little you can do about
-this aside from complaining to your site postmaster, and nothing at
-all fetchmail can do about it!
-
-
More likely you'll find that the server copy looks OK. In that case -either the POP/IMAP server or fetchmail is doing the mangling. To -determine which, you'll need to telnet to the server port and simulate -a fetchmail session yourself. This is not actually hard (both POP3 -and IMAP are simple, text-only, line-oriented protocols) but requires -some attention to detail. You should be able to use a fetchmail -v -log as a model for a session, but remember that the "*" in your LOGIN -or PASS command dump has to be replaced with your actual password. +
This will capture what fetchmail gets from the server, except
+for (a) the extra Received header line fetchmail prepends, (b)
+header address changes due to rewrite
, and (c) any
+end-of-line changes due to the forcecr
and
+stripcr
options. MBOX will in fact contain what
+programs downstream of fetchmail see.
The most common causes of mangling are bugs and +misconfigurations in those downstream programs. If MBOX looks +unmangled, you will know that is what is going on and that it is +not fetchmail's problem. Take a look at the other FAQ items in this +section for possible clues about how to fix your problem.
+ +If MBOX looks mangled, the next thing to do is compare it with
+your actual server mailbox (if possible). That's why you specified
+keep
, so the server copy would not be deleted. If your
+server mailbox looks mangled, programs upstream of your server
+mailbox are at fault. Unfortunately there is probably little you
+can do about this aside from complaining to your site postmaster,
+and nothing at all fetchmail can do about it!
More likely you'll find that the server copy looks OK. In that +case either the POP/IMAP server or fetchmail is doing the mangling. +To determine which, you'll need to telnet to the server port and +simulate a fetchmail session yourself. This is not actually hard +(both POP3 and IMAP are simple, text-only, line-oriented protocols) +but requires some attention to detail. You should be able to use a +fetchmail -v log as a model for a session, but remember that the +"*" in your LOGIN or PASS command dump has to be replaced with your +actual password.
The objective of manually simulating fetchmail is so you can see -exactly what fetchmail sees. If you see a mangled message, then your -server is at fault, and you probably need to complain to your -mailserver administrators. However, we like to know what the broken -servers are so we can warn people away from them. So please send -us a transcript of the session including the mangling and the -server's initial greeting line. Please tell us anything else +exactly what fetchmail sees. If you see a mangled message, then +your server is at fault, and you probably need to complain to your +mailserver administrators. However, we like to know what the broken +servers are so we can warn people away from them. So please send us +a transcript of the session including the mangling and the +server's initial greeting line. Please tell us anything else you think might be useful about the server, like the server host's -operating system. +operating system.
If your manual fetchmail simulation shows an unmangled message, -congratulations. You've found an actual fetchmail bug, which is a -pretty rare thing these days. Complain to us and we'll fix it. +congratulations. You've found an actual fetchmail bug, which is a +pretty rare thing these days. Complain to us and we'll fix it. Please include the session transcript of your manual fetchmail -simulation along with the other things described in the FAQ entry on -reporting bugs. - -
This may happen in versions of fetchmail after 4.4.1 and before 4.4.8. -Versions after 4.4.1 use POP3's TOP command rather than RETR, in order -to avoid marking the message seen (leaving it unseen is helpful for -later recovery if you lose your connection in the middle of a -retrieval). - -
Versions of fetchmail from 4.4.2 through 4.4.7 had a bad interaction -with Eudora qpopper versions 2.3 and later. The TOP bounds check was -fooled by an overflow condition in the TOP argument. Decrementing the -TOP argument in 4.4.7 fixed this. - -
Fix: Upgrade to a later version of fetchmail. - -
Workaround: set the fetchall
option. Under POP3
-this has the side effect of forcing RETR use.
-
-
This isn't fetchmail's doing -- fetchmail never drops lines in message -bodies or attachments. It may be your POP server, or it may be the -sender's mail user agent (or a bad combination of both). - -
The Mail Max POP3 server and the InterChange and Imail IMAP servers -are known to simply drop MIME attachments when uploading messages. -We've had sporadic reports of problems with Microsoft Exchange and -Outlook servers. Windows- and NT-based POP servers seem especially -prone to mangle attachments. If you are running one of these, -replacing your server with a Unix machine is probably the only -effective solution. +simulation along with the other things described in the FAQ entry +on reporting bugs.
+ +The information that used to be here pertained to fetchmail 4.4.7 or + older, which should not be used. Use a recent fetchmail version.
+ +Fetchmail doesn't discard attachments; fetchmail doesn't have any idea +that attachments are there. Fetchmail treats the body of each message as +an uninterpreted byte stream and passes it through without alteration. +If you are not receiving attachments through fetchmail, it is because +your mailserver is not sending them to you.
+ +The fix for this is to replace your mailserver with one that works. +If its operating system makes this difficult, you should replace its +operating system with one that works. Windows- and NT-based POP servers +seem especially prone to mangle attachments. If you are running one +of these, replacing your server with a Unix machine is probably the +only effective solution.
+ +We've had sporadic reports of problems with Microsoft Exchange and +Outlook servers. These sometimes randomly fail to ship +attachments to your client. This is a known bug, acknowledged by +Microsoft.
+ +They may also mangle the attachments they do pass through. If you +see unreadable attachments with a ContentType of "application/x-tnef", +you're having this problem. The TNEF utility may +help.
+ +The Mail Max POP3 server and the InterChange and Imail IMAP +servers are known to simply drop MIME attachments when uploading +messages.
We've also had a report that Lotus Notes sometimes trashes the -MIME type of messages. In particular, it seems to modify MIME -headers introducing type application/pdf, mangling the type -to application/octet-stream. It may corrupt other MIME types -as well. +MIME type of messages. In particular, it seems to modify MIME +headers of type application/pdf, mangling the type to +application/octet-stream. It may corrupt other MIME types as +well.
The IMAP service of Lotus Domino has a known bug in the way it -generates MIME Content-type headers (observed on Lotus Domino 5.0.2b). -It's a subtle one that doesn't show up when Netscape Messenger and -other clients use a FETCH BODY[] to grab the whole message. When -fetchmail uses FETCH RFC822.HEADER and FETCH RFC822.TEXT to get first -the header and then the body, Domino generates different Boundary tags -for each part, .e.g. one tag is declared in the Content-type header and -another is used to separate the MIME parts in the body. This doesn't -work. (I have heard a rumor that this bug is scheduled to be fixed -in Domino release 6; you can find a workaround at contrib/domino.) - -
Another rich source of attachment problems is Microsoft Exchange and -Microsoft Outlook. If you see unreadable attachments with a -ContentType of "application/x-tnef", you're having this problem. The -TNEF utility -may help. - -
Rob Funk explains: Unfortunately there also remain many mail user -agents that don't write correct MIME messages. One big offender is Sun -MailTool attachments, which are formatted enough like MIME that some -programs could get confused; these are generated by the mailtool and -dtmail programs (the mail programs in Sun's OpenWindows and CDE -environments). - -
One solution to problems related to misformatted MIME attachments is -the emil +generates MIME Content-type headers (observed on Lotus Domino +5.0.2b). It's a subtle one that doesn't show up when Netscape +Messenger and other clients use a FETCH BODY[] to grab the whole +message. When fetchmail uses FETCH RFC822.HEADER and FETCH +RFC822.TEXT to get first the header and then the body, Domino +generates different Boundary tags for each part, e.g. one tag is +declared in the Content-type header and another is used to separate +the MIME parts in the body. This doesn't work. (I have heard a +rumor that this bug is scheduled to be fixed in Domino release 6; +you can find a workaround at contrib/domino.)
+ +Rob Funk explains: Unfortunately there also remain many mail +user agents that don't write correct MIME messages. One big +offender is Sun MailTool attachments, which are formatted enough +like MIME that some programs could get confused; these are +generated by the mailtool and dtmail programs (the mail programs in +Sun's OpenWindows and CDE environments).
+ +One solution to problems related to misformatted MIME +attachments is the emil program; see its tutorial -file at that site for details on emil. It is useful for -converting character sets, attachment encodings, and attachment -formats. At this writing, emil does not appear to have been -maintained since a patch to version 2.1.0beta9 in late 1997, but it is -still useful. +file at that site for details on emil. It is useful for converting +character sets, attachment encodings, and attachment formats. At +this writing, emil does not appear to have been maintained since a +patch to version 2.1.0beta9 in late 1997, but it is still +useful.
-One good way of using emil is from within procmail. You can have +
One good way of using emil is from within procmail. You can have procmail look for signs of problematic message formatting, and pipe -those messages through emil to be fixed. emil will not always be able -to fix the problem, in which case the message is unchanged. +those messages through emil to be fixed. emil will not always be +able to fix the problem, in which case the message is +unchanged.
-A possible rule to be inserted into a .procmailrc file for using emil -would be: +
A possible rule to be inserted into a .procmailrc file for using +emil would be:
:0HB @@ -2679,139 +3168,187 @@ would be: }-
The "1^1" in the conditions is a way of specifying to procmail that if -any one of the four listed expressions is found in the message, the -total condition is considered true, and the message gets passed into -emil. These four subconditions check whether the message has a Sun -attachment, a binhex attachment, or a uuencoded attachment; there are -others that could be added to check these things better and to check -other relevant conditions. The "LOG=" line writes a line into the -procmail log; the lone double-quote beginning the following line makes -sure the log entry gets an end-of-line character. The call to gawk -(GNU awk) is for fixing end-of-line conventions, since emil sometimes -leaves those in the format of the originating machine; it could -probably be replaced with a sed subsitution. - -
The emil call itself tries to ensure that the message uses: +
The "1^1" in the conditions is a way of specifying to procmail +that if any one of the four listed expressions is found in the +message, the total condition is considered true, and the message +gets passed into emil. These four subconditions check whether the +message has a Sun attachment, a binhex attachment, or a uuencoded +attachment; there are others that could be added to check these +things better and to check other relevant conditions. The "LOG=" +line writes a line into the procmail log; the lone double-quote +beginning the following line makes sure the log entry gets an +end-of-line character. The call to gawk (GNU awk) is for fixing +end-of-line conventions, since emil sometimes leaves those in the +format of the originating machine; it could probably be replaced +with a sed subsitution.
+ +The emil call itself tries to ensure that the message uses:
Most of these (the primary exceptions being the character set and the -Apple binary format) are as they should be for good internet -interoperability.
- +
Most of these (the primary exceptions being the character set +and the Apple binary format) are as they should be for good +internet interoperability.
+Some mail servers (Lotus Domino is a suspect here) mangle Sun-formatted messages, so the conversion to MIME needs to happen -before such programs see the message. The ideal is to rid the world -of Sun-formatted messages: don't use mailtool for sending attachments -(it doesn't understand MIME anyway, and most of the world doesn't -understand its attachments, so it really shouldn't be used at all), -and make sure dtmail is set to use MIME rather than mailtool's format. - -
This isn't fetchmail's problem either; fetchmail doesn't know anything -about mail attachments and doesn't treat them any differently from -plain message data. - -
The most usual cause of this problem seems to be bugs in your network -transport layer's capability to handle the very large TCP/IP packets -that attachments tend to turn into. You can test this theory by trying to -download the offending message through a webmail account; using HTTP -for the message tends to simulate large-packet stress rather well, and -you will probably find that the messages that seem to be choking -fetchmail will make your HTTP download speed drop to zero. - -
This problem can be caused by subtle bugs in the packet-reassembly -layer of your TCP/IP stack; these often don't manifest at normal -packet sizes. It may also be caused by malfunctioning path-MTU -discovery on the mailserver. Or, if there's a modem in the link, -it may be because the attachment contains the Hayes mode escape "+++". - -
Blame it on that rancid pile of dung and offal called Microsoft -Exchange. Due to the problem described in S2, the -IMAP support in fetchmail cannot follow the IMAP protocol 100%. Most -of the time it doesn't matter, but if you combine it with an SMTP -server that behaves unusually, you'll get a spurious ) at message end. - -
One piece of software that can trigger this is the Interchange mail -server, as used by, e.g., mailandnews.com. Here's what happens: - -
1. Someone sends mail to your account. The last line of the message -contains text. So at the SMTP level, the message ends with, e.g. -"blahblah\r\n.\r\n" - -
2. The SMTP handler sees the final "\r\n.\r\n" and recognizes the -end of the message. However, instead of doing the normal thing, which -is tossing out the ".\r\n" and leaving the first '\r\n' as part of the -email body, Interchange throws out the whole "\r\n.\r\n", and leaves -the email body without any line terminator at the end of it. RFC821 -does not forbid this, though it probably should. - -
3. Fetchmail, or some other IMAP client, asks for the message. IMAP -returns it, but it's enclosed inside parentheses, according to the -protocol. The message size in bytes is also present. Because the -message doesn't end with a line terminator, the IMAP client sees: - - ....blahblah)... - -where the ')' is from IMAP. - -
4. Fetchmail only deals with complete lines, and can't trust the -stated message size because Microsoft Exchange fscks it up. +before such programs see the message. The ideal is to rid the world +of Sun-formatted messages: don't use mailtool for sending +attachments (it doesn't understand MIME anyway, and most of the +world doesn't understand its attachments, so it really shouldn't be +used at all), and make sure dtmail is set to use MIME rather than +mailtool's format.
+ +Fetchmail doesn't know anything about mail attachments and doesn't +treat them any differently from plain message data.
+ +The most usual cause of this problem seems to be bugs in your +network transport layer's capability to handle the very large +TCP/IP packets that attachments tend to turn into. You can test +this theory by trying to download the offending message through a +webmail account; using HTTP for the message tends to simulate +large-packet stress rather well, and you will probably find that +the messages that seem to be choking fetchmail will make your HTTP +download speed drop to zero.
+ +This problem can be caused by subtle bugs in the +packet-reassembly layer of your TCP/IP stack; these often don't +manifest at normal packet sizes. It may also be caused by +malfunctioning path-MTU discovery on the mailserver. Or, if there's +a modem in the link, it may be because the attachment contains the +Hayes mode escape "+++".
+ +Due to the problem described in S2, the +IMAP support in fetchmail cannot follow the IMAP protocol 100 %. +Most of the time it doesn't matter, but if you combine it with an +SMTP server that behaves unusually, you'll get a spurious ) at +the message end.
+ +One piece of software that can trigger this is the Interchange +mail server, as used by, e.g., mailandnews.com. Here's what +happens:
+ +5. As a result, fetchmail takes the final 'blahblah)' and puts it -at the end of the message it forwards on. If you have verbosity on, -you'll get a message about actual != expected. - -
There is no fix for this. The nuke mentioned in S2 looks more tempting all the time. +
+ ....blahblah)... +-
where the ')' is from IMAP.
This is a feature, not a bug. It's in line with normal practice for -system daemons and allows you to suppress logging by removing the log, -without hacking potentially fragile startup scripts. To get around -it, just touch(1) the logfile before you run fetchmail (this will have -no effect on the contents of the logfile if it already exists). +
Fetchmail uses the local sendmail to perform final delivery, which -Netscape and other clients doesn't do; the announcement of new messages -is done by a daemon that sendmail pokes. There should be a ``biff'' -command to control this. Type +
There is no fix for this.
+ +Domino 6 IMAP was found by Anthony Kim in February 2006 to +erroneously omit the "Content-Transfer-Encoding" header in messages +downloaded through IMAP, causing messages to display improperly. This +happened with Domino's incoming mail format configured to "Prefers +MIME". Solution: switch Domino to "Keep in Sender's format".
+ +Reference: Anthony + Kim's list post +
+ +Fetchmail is sometimes reported to deliver partial messages. This +is usually related to network outages that occur while fetchmail is +downloading a message body. In such cases, fetchmail has downloaded a +complete header, so your header will be intact. The message body will be +truncated, and fetchmail will later attempt to redownload the +message (providing the server is standards conformant).
+ +The reason for the truncation is that fetchmail streams the body +directly from the POP3/IMAP server into the SMTP/LMTP server or MDA (in +order to save memory), so fetchmail has already written a part of the +message before it notices it will be incomplete, and fetchmail cannot +abort a transaction it has started, and it's unclear if it ever will be +able to, because this is not standardized and the outcome will depend on +the receiving software (be it SMTP/LMTP or MDA).
+ +This is a feature, not a bug. It's in line with normal practice +for system daemons and allows you to suppress logging by removing +the log file, without hacking potentially fragile startup scripts. +To get around it, just touch(1) the logfile before you run fetchmail +(this will have no effect on the contents of the logfile if it already +exists).
+ +Fetchmail uses the local sendmail to perform final delivery, +which Mozilla and other clients don't do; the announcement of +new messages is done by a daemon that sendmail pokes. There should +be a "biff" command to control this. Type
biff n-to turn it off. If this doesn't work, try the command +
to turn it off. If this doesn't work, try the command
-chmod -x `tty` +chmod -x $(tty)-which is essentially what
biff -n
will do. If this
-doesn't work, comment out any reference to ``comsat'' in your
-/etc/inetd.conf file and restart inetd.
+which is essentially what biff -n
will do. If this
+doesn't work, comment out any reference to "comsat" in your
+/etc/inetd.conf file and reload (or restart) inetd.
In Slackware Linux distributions, the last line in /etc/profile is +
In Slackware Linux distributions, the last line in /etc/profile +is
biff y @@ -2825,182 +3362,268 @@ biff n to solve the problem system-wide. -
-O3. Does fetchmail reread its rc file every poll cycle?
- -No, but versions 5.2.2 and later will notice when you modify your rc -file and restart, reading it. +
O3. Does fetchmail reread its rc file +every poll cycle?
-
-O4. Why do deleted messages show up again when I take -a line hit while downloading?
+No, but versions 5.2.2 and later will notice when you modify +your rc file and restart, reading it. Note that this causes troubles if +you need to provide a password via the console, unless you're running in +--nodetach mode.
-Because you're using a POP3 other than Qualcomm qpopper, or an IMAP -with a long expunge interval. +
O4. Why do deleted messages show up again +when I take a line hit while downloading?
-According to the POP3 RFCs, deletes aren't actually performed until -you issue the end-of-session QUIT command. Fetchmail cannot fix this, -because doing it right takes cooperation from the server. There are -two possible remedies: +
According to the POP3 RFCs, deletes aren't actually performed +until you issue the end-of-session QUIT command. Fetchmail cannot +fix this, but there is a workaround: use the --expunge option with a +reasonably low figure that works for you. Try 10 for a start.
-One is to switch to qpopper (the free POP3 server from Qualcomm, -the Eudora people). The qpopper software violates the POP3 RFCs by -doing an expunge (removing deleted messages) on a line hangup, as well -as on processing a QUIT command. - -
The other (which we recommend) is to switch to IMAP. IMAP has an explicit expunge -command and fetchmail normally uses it to delete messages immediately -after they are downloaded. +
IMAP is less susceptible to this problem, because the "deleted" +message marks are persistent, but they aren't in POP3. Note that the +--expunge default for IMAP is different than the default for POP3.
If you get very unlucky, you might take a line hit in the window -between the delete and the expunge. If you've set a longer expunge -interval, the window gets wider. This problem should correct itself -the next time you complete a successful query. +between the delete and the expunge. If you've set a longer expunge +interval, the window gets wider. This problem should correct itself +the next time you complete a successful query.
-
-O5. Why is fetched mail being logged with my name, not the real From address?
+O5. Why is fetched mail being logged with +my name, not the real From address?
-Because logging is done based on the address indicated by the sending -SMTP's MAIL FROM, and some listeners are picky about that address. +
Because logging is done based on the address indicated by the +sending SMTP's MAIL FROM, and some listeners are picky about that +address.
-Some SMTP listeners get upset if you try to hand them a MAIL FROM -address naming a different host than the originating site for your -connection. This is a feature, not a bug -- it's supposed to help -prevent people from forging mail with a bogus origin site. (RFC 1123 -says you shouldn't do this exclusion...) +
Some SMTP listeners get upset if you try to hand them a MAIL +FROM address naming a different host than the originating site for +your connection. This is a feature, not a bug -- it's supposed to +help prevent people from forging mail with a bogus origin site. +(RFC 1123 says you shouldn't do this exclusion...)
Since the originating site of a fetchmail delivery connection is -localhost, this effectively means these picky listeners will barf on -any MAIL FROM address fetchmail hands them with an @ in it! +localhost, this effectively means these picky listeners will barf +on any MAIL FROM address fetchmail hands them with an @ in it!
-Versions 2.1 and up try the header From address first and fall back to -the calling-user ID. So if your SMTP listener isn't picky, the log -will look right. +
Versions 2.1 and up try the header From address first and fall +back to the calling-user ID. So if your SMTP listener isn't picky, +the log will look right.
-
-O6. I'm seeing long sendmail delays or hangs near the start of each poll cycle.
+O6. I'm seeing long sendmail delays or +hangs near the start of each poll cycle.
-Sendmail does a hostname lookup when it first starts up, and also each -time it gets a HELO in listener mode. +
Sendmail does a hostname lookup when it first starts up, and +also each time it gets a HELO in listener mode.
-Your resolver configuration may be causing one of these lookups to -fail and time out. Check
/etc/resolv.conf
and -/etc/hosts
file. Make sure your hostname and -fully-qualified domain name are both in/etc/hosts
, and -that hosts is looked at before DNS is queried. You probably also want -your remote mail server(s) to be in the hosts file. +Your resolver configuration may be causing one of these lookups +to fail and time out. Check your
/etc/resolv.conf
, +/etc/host.conf
,/etc/nsswitch.conf
(if you +have the latter two) and you/etc/hosts
files. Make sure +your hostname and fully-qualified domain name are both in +/etc/hosts
, and that hosts is looked at before DNS is +queried. You probably also want your remote mail server(s) to be in the +hosts file.You can suppress the startup-time lookup if need to by reconfiguring -with
-FEATURE(nodns)
. +withFEATURE(nodns)
.Configuring your bind library to cache DNS lookups locally may help, -and is a good idea for speeding up other services as well. Switching to -a faster MTA like qmail or exim might help. +
Configuring your bind library to cache DNS lookups locally may +help, and is a good idea for speeding up other services as well. +Switching to a faster MTA like Postfix might help.
-
-O7. Why doesn't fetchmail deliver mail in date-sorted order?
+O7. Why doesn't fetchmail deliver mail in +date-sorted order?
-Because that's not the order the server hands it to fetchmail in. +
Because that's not the order the server hands it to fetchmail +in.
-Fetchmail getting mail from a POP server delivers mail in the order -that your server delivers mail. Fetchmail can't do anything about -this; it's a limitation of the underlying POP protocol. +
Fetchmail getting mail from a POP server delivers mail in the +order that your server delivers mail. Fetchmail can't do anything +about this; it's a limitation of the underlying POP protocol.
-In theory it might be possible for fetchmail in IMAP mode to sort -messages by date, but this would be in violation of two basics of -fetchmail's design philosophy: (a) to be as simple and transparent a -pipe as possible, and (b) to hide, rather than emphasize, the -differences between the remote-fetch protocols it uses. +
In theory it might be possible for fetchmail in IMAP mode to +sort messages by date, but this would be in violation of two basics +of fetchmail's design philosophy: (a) to be as simple and +transparent a pipe as possible, and (b) to hide, rather +than emphasize, the differences between the remote-fetch protocols +it uses.
-Re-ordering messages is a user-agent function, anyway. +
Re-ordering messages is a user-agent function, anyway.
-
-O8. I'm using pppd. Why isn't my monitor option working?
+O8. I'm using pppd. Why isn't my monitor +option working?
-There is a combination of circumstances that can confuse fetchmail. -If you have set up demand dialing with pppd, and pppd has an idle -timeout, and you have lcp-echo-interval set, then the +
There is a combination of circumstances that can confuse +fetchmail. If you have set up demand dialing with pppd, and pppd +has an idle timeout, and you have lcp-echo-interval set, then the lcp-echo-interval time must be longer than the pppd idle timeout. -Otherwise it is going keep increasing the packet counters that fetchmail -relies upon, triggering fetchmail into polling after its own delay -interval and thus preventing the pppd link from ever reaching its -inactivity timeout. - -
-O9. Why does fetchmail keep retrieving the same messages -over and over?
- -First, check to see that you haven't enabled the keep -and fetchall option. If you have, turn keep off. - -
There are various forms of lossage involving the POP3 UIDL feature -that can lead to all your old messages being seen again after a line -drop. I have given up trying to fix these, as the UIDL code breaks -worse every time I touch it. The problem is fundamental; maintaining -and garbage-collecting the right kind of client-side state is just -hard. Whoever put UIDLs in RFC1725 and removed LAST should be hung -up by his thumbs and whipped with scorpions. The right answers are -either (a) live with the occasional breakage, (b) switch to IMAP4, -or (c) fix the code yourself and send me a patch. Unless you choose -(c), I don't want to hear about it. - -
This can also happen when some other mail client is logged in to your -mail server, if it uses a simple exclusive-locking scheme (and many, -especially most POP3 servers, do exactly that). Your fetchmail is -able to retrieve the messages, but because the mailbox is write-locked -by the other instance yours can neither mark messages seen or delete them. -The solution is to either (a) wait for the other client to finish, or (b) -terminate it. - -
James Stevens <James.Stevens@kyzo.com> writes:
- - -
We had a Linux box dialing the Net and collecting mail from an NT POP3 -server. Fetchmail was correctly collecting and deleting each e-mail -one by one. However,the dial-up connection was very unreliable and -would often just drop out in the middle of a session. - -
Interestingly, unless the TCP POP3 connection was terminated normally -(I guess with a POP3 "QUIT" command) NT would then roll back all the -deletes !!! - -
This meant if the first e-mail was very large it might just end up -continuously collecting it, basically jamming the queue. Or, if the -queue became very full itmight never get a long enough phone -connection to retrieve the entire mailbox, and NT would roll back any -deletes, so it would end up collecting (and delivering) the first few -e-mails again and again. As the POP3 mailbox became fuller and fuller -the chances of getting a connection long enough to collect theentire -mailbox became smaller and smaller. - -
Our solution was to make fetchmail only collect a few (say 5 or 10) -e-mails at atime, thus trying to ensure that the POP3 connection is -terminated correctly. -
- -Unfortunately, this is exactly the way POP3 servers are supposed -to behave on a line drop, according to the RFCs. I recommend -switching to IMAP and using a short expunge interval. - -
-O10. Why is the received date on all my messages the same?
- -This is a design choice in your MTA, not fetchmail. It's taking the received -date from the last Received header.- -
-
Back to Fetchmail Home Page - | To Site Map - | $Date: 2002/02/01 02:14:23 $
+Otherwise it is going keep increasing the packet counters that
+fetchmail relies upon, triggering fetchmail into polling after its
+own delay interval and thus preventing the pppd link from ever
+reaching its inactivity timeout.
+
+O9. Why does fetchmail keep retrieving the +same messages over and over?+ +First, check to see that you haven't enabled the +keep and fetchall option. If you have, +turn one of them off - which one, depends on why they have been set in +the first place, and to a lesser degree on the upstream server. + +This can also happen when some other mail client is logged in to +your mail server, if it uses a simple exclusive-locking scheme (and +many, especially most POP3 servers, do exactly that). Your +fetchmail is able to retrieve the messages, but because the mailbox +is write-locked by the other instance yours can neither mark +messages seen or delete them. The solution is to either (a) wait +for the other client to finish, or (b) terminate it. + +
+
+ |
Back to Fetchmail Home +Page | +$Date$ | +