Slow POP3 with Dovecot and/or Courier

[makedo]

Hi everyone,

I've got a problem with POP3 access on my server. The access to the mails is rather slow. I am using Outlook XP on Windows for retrieving the mails, and it seems to "pause" slightly after each email. All emails are downloaded fine, and there are no timeouts, however it takes up a lot of time.

I have tried both Dovecot and Courier on the server. This is an issue with TLS or without TLS. I am authenticating against plain UNIX users (basically changed nothing in the configuration scripts, except the TLS cert). This is on a relatively unchanged Suse 9.3 system.

No error or warning messages in the log.

I am really at a loss here - what could possibly cause this problem? The server should be a lot faster than this (3 GHz, plenty of RAM, fast Internet connection).

My previous server was less capable and worked fine, also with Outlook, same setup (also with courier, but on Debian). I just can't seem to find the relevant difference...

Any ideas? Thanks a lot!

[falko]

Sounds like a firewall problem. What's the output of

iptables -L

? Might also be a problem with your desktop firewall, if you use one.

[makedo]

Thanks for your answer!

iptables is set to accept anything:

---
Chain INPUT (policy ACCEPT)
target prot opt source destination

Chain FORWARD (policy ACCEPT)
target prot opt source destination

Chain OUTPUT (policy ACCEPT)
target prot opt source destination
---

I also do not have a desktop firewall.

I tried using Thunderbird for a change, with the same result. I have also verified that the CLIENT seems to pause after each email, i.e. before sending the next "RCPT x" command to the POP server. (some 0.3 seconds to 1 second delay).

I still have NO idea what's causing this...

[falko]

Do you see any errors in your log files?

[makedo]

No related errors in any of the mail log files (in fact, no errors at all for pop3). /var/log/mail logs a typical session like this:

Sep 7 11:20:20 servername pop3d: Connection, ip=[::ffff:xx.xx.xx.xx]
Sep 7 11:20:20 servername pop3d: LOGIN, user=makedo, ip=[::ffff:xx.xx.xx.xx]
Sep 7 11:20:24 servername pop3d: LOGOUT, user=makedo, ip=[::ffff:xx.xx.xx.xx], top=0, retr=10128, time=4

Hm... any other ideas?

[falko]

Originally Posted by makedo

Sep 7 11:20:20 servername pop3d: Connection, ip=[::ffff:xx.xx.xx.xx]
Sep 7 11:20:20 servername pop3d: LOGIN, user=makedo, ip=[::ffff:xx.xx.xx.xx]
Sep 7 11:20:24 servername pop3d: LOGOUT, user=makedo, ip=[::ffff:xx.xx.xx.xx], top=0, retr=10128, time=4

Hm... any other ideas?

Didn't you say you are using Courier? Your logs show another POP3 daemon. What's the output of

netstat -tap

?

[makedo]

Netstat coming up...:

Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name
tcp        0      0 *:pop3                  *:*                     LISTEN      12369/couriertcpd

The courier package is from Suse 9.3. Started with /etc/init.d/courier-pop3.

[falko]

Ok, it's Courier then.
What's the output of

ps aux

? What's the output of

updatedb
locate courier

?

[makedo]

ps aux:

USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
root     26128  0.0  0.0   1380   464 ?        S    Sep05   0:00 /usr/sbin/courierlogger -pid=/var/run/authdaemon.courier-imap/pid -start /usr/lib/courier-imap/authlib/authdaemond.plain
root     26129  0.0  0.0   1728   508 ?        S    Sep05   0:00 /usr/lib/courier-imap/authlib/authdaemond.plain
root     26130  0.0  0.0   1924   728 ?        S    Sep05   0:00 /usr/lib/courier-imap/authlib/authdaemond.plain
root     26131  0.0  0.0   1924   728 ?        S    Sep05   0:00 /usr/lib/courier-imap/authlib/authdaemond.plain
root     26141  0.0  0.0   1924   728 ?        S    Sep05   0:00 /usr/lib/courier-imap/authlib/authdaemond.plain
root     26142  0.0  0.0   1924   728 ?        S    Sep05   0:00 /usr/lib/courier-imap/authlib/authdaemond.plain
root     26177  0.0  0.0   1924   728 ?        S    Sep05   0:00 /usr/lib/courier-imap/authlib/authdaemond.plain
root     23718  0.0  0.0   1480   520 ?        S    14:57   0:00 /usr/lib/courier-imap/couriertcpd -address=0 -stderrlogger=/usr/sbin/courierlogger -stderrloggername=pop3d -maxprocs=40 -maxperip=4 -pid=/var/run/pop3d.pid -nodnslookup -noidentlookup 110 /usr/sbin/pop3login /usr/lib/courier-imap/authlib/authdaemon /usr/sbin/pop3d Maildir
root     23720  0.0  0.0   1252   296 ?        S    14:57   0:00 /usr/sbin/courierlogger pop3d

locate courier

/etc/courier
/etc/courier/authdaemonrc
/etc/courier/authdaemonrc.dist
/etc/courier/imapd
/etc/courier/imapd-ssl
/etc/courier/imapd-ssl.dist
/etc/courier/imapd.cnf
/etc/courier/imapd.dist
/etc/courier/pop3d
/etc/courier/pop3d-ssl
/etc/courier/pop3d-ssl.dist
/etc/courier/pop3d.cnf
/etc/courier/pop3d.dist
/etc/courier/quotawarnmsg.example
/etc/init.d/courier-authdaemon
/etc/init.d/courier-imap
/etc/init.d/courier-imap-ssl
/etc/init.d/courier-pop3
/etc/init.d/courier-pop3-ssl
/etc/init.d/rc3.d/K09courier-pop3-ssl
/etc/init.d/rc3.d/K10courier-authdaemon
/etc/init.d/rc3.d/S12courier-authdaemon
/etc/init.d/rc3.d/S13courier-pop3-ssl
/etc/init.d/rc5.d/K09courier-pop3-ssl
/etc/init.d/rc5.d/K10courier-authdaemon
/etc/init.d/rc5.d/S12courier-authdaemon
/etc/init.d/rc5.d/S13courier-pop3-ssl
/usr/lib/courier-imap
/usr/lib/courier-imap/authlib
/usr/lib/courier-imap/authlib/authdaemon
/usr/lib/courier-imap/authlib/authdaemond
/usr/lib/courier-imap/authlib/authdaemond.plain
/usr/lib/courier-imap/couriertcpd
/usr/lib/courier-imap/makedatprog
/usr/sbin/courierlogger
/usr/sbin/couriertls
/usr/sbin/rccourier-authdaemon
/usr/sbin/rccourier-imap
/usr/sbin/rccourier-imap-ssl
/usr/sbin/rccourier-pop3
/usr/sbin/rccourier-pop3-ssl
/usr/share/courier-imap
/usr/share/courier-imap/configlist
/usr/share/courier-imap/configlist.ldap
/usr/share/courier-imap/makeuserdb
/usr/share/courier-imap/mkimapdcert
/usr/share/courier-imap/mkpop3dcert
/usr/share/courier-imap/pop3d.pem
/usr/share/courier-imap/pw2userdb
/usr/share/courier-imap/sysconftool
/usr/share/courier-imap/userdb
/usr/share/courier-imap/vchkpw2userdb
/usr/share/doc/packages/courier-imap
/usr/share/doc/packages/courier-imap/AUTHORS
/usr/share/doc/packages/courier-imap/BUGS
/usr/share/doc/packages/courier-imap/COPYING
/usr/share/doc/packages/courier-imap/README
/usr/share/doc/packages/courier-imap/README.authdebug.html
/usr/share/doc/packages/courier-imap/README.authdebug.html.in
/usr/share/doc/packages/courier-imap/README.authmysql.html
/usr/share/doc/packages/courier-imap/README.authmysql.myownquery
/usr/share/doc/packages/courier-imap/README.authpostgres.html
/usr/share/doc/packages/courier-imap/README.imap
/usr/share/doc/packages/courier-imap/README.ldap
/usr/share/doc/packages/courier-imap/README.maildirquota
/usr/share/doc/packages/courier-imap/README.sharedfolders
/usr/share/man/man1/courierlogger.1.gz
/usr/share/man/man1/couriertcpd.1.gz
/usr/share/man/man8/courier-imapd.8.gz
/usr/share/munin/plugins/courier_
/usr/share/munin/plugins/courier_mta_mailqueue
/usr/share/munin/plugins/courier_mta_mailstats
/usr/share/munin/plugins/courier_mta_mailvolume
/var/adm/YaST/InstSrcManager/IS_CACHE_0x00000001/MEDIA/suse/i586/courier-imap-3.0.8-3.i586.rpm
/var/run/authdaemon.courier-imap
/var/run/authdaemon.courier-imap/pid
/var/run/authdaemon.courier-imap/pid.lock
/var/run/authdaemon.courier-imap/socket
/var/run/couriersslcache

[falko]

Did you check the settings in the configuration files in /etc/courier?