FreeBSD 4.8-STABLE + UW-IMAP + Sendmail problems.
s at teven.org
Thu Sep 18 16:57:12 PDT 2003
I run what has, until recently, been a fairly stable and reliable mail
server setup. On about the 12th of September, the server and its DNS was
offline due to a large DDoS. When the machine came alive again,
everything appeared to be working fine. Currently, another almost
identical server that was also similarly affected by the DDoS is
On the 14th, users suddenly started having troubles checking their email
using POP3. Login attempts would time out. Investigation of
/var/log/maillog showed several interesting messages, such as (of
course, hostnames and IP addresses have been changed):
Sep 18 09:58:10 wgservices ipop3d: Command stream end of file
while reading line user=stan host=[10.0.0.22]
Sep 18 15:06:45 wgservices ipop3d: Auth user=wgs host=[10.0.0.12]
Sep 18 15:06:45 wgservices ipop3d: Connection reset by peer while
reading line user=wgs host=[10.0.0.12]
Sep 18 09:37:11 wgservices ipop3d: Error opening or locking INBOX
Sep 18 09:37:11 wgservices ipop3d: Login user=wgs host=UNKNOWN no
Sep 18 09:37:11 wgservices ipop3d: Logout user=wgs host=UNKNOWN
The confusing thing for me is that other users, such as myself, can
check their mail using POP3 perfectly. Only some accounts seem to be
unable to do so. I tried looking for and removing lock files, checking
disk-free space, installing and using qpopper, and even went as far as
removing one user's account and readding it - but this had no impact on
the problem. Why ipop3d seems unable to determine the host of a machine
on the LAN is a bit puzzling - it should be 10.0.0.22.
When I telnet to the POP3 server from a remote site, I appear to be able
to access it normally:
Connected to mail.whatever.com
Escape character is ''.
+OK POP3 whatever.com v2003.83 server ready
+OK User name accepted, password please
+OK Mailbox open, 0 messages
Connection closed by foreign host.
Does anyone have any ideas what this problem is caused by and how it can
be fixed? We're using Sendmail in conjunction with Mailscanner, Sophos
antivirus, and Spamassassin, and the Eudora and Mozilla mail clients.
Several machines check the same accounts (rather than having an alias -
not my ideal, but I'm just the monkey that does what's asked).
Apparently, similar problems can be caused by clients such as Outlook
Express (which we don't use) failing to disconnect cleanly from the
server, or something like that.
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