pop3 timeouts

[andron26]

Hello,

I have ISPConfig with OpenSuse 10.2 installed by perfect setup guide. Everything worked fine for about 6 months. Now I have users which started to have timeouts when they uses pop3 e-mail clients and download messages with bigger attachments. They have to try several times before they can retrieve e-mail. When they connect to webmail they can retrieve e-mail without problem.
What could be the reason? There are a lot of hard disk space, CPU utilization is about 30%, there is enough RAM. I'have changed maxperip value in pop3d config file but nothing helped.
How can I see detailed pop3 log? Is it possible to trace connection to pop3 server? In mail log there is only who and when connected.

Thanks in advance and sorry for my english.

[till]

And you use maildir as described in the perfect setup or mbox?

[andron26]

I use Maildir.

[falko]

Any errors in your logs? What are the outputs of netstat -tap, df -h and repquota -avug?

[andron26]

Attached output.

[andron26]

Netstat shows a lot of time_wait connections on port 110. What does this mean?

[falko]

Might be some kind of DOS attack. That would explain the timeouts your users sometimes have when they try to download mails...

[andron26]

Is it possible to log detail connection between mail client and pop3 server?

[falko]

It's logged in the mail log (/var/log/mail on SUSE).

[andron26]

I know but I need more detailed log. I mean full connection log between client and server (HELLO, USER, PASS, STAT etc.)

[till]

You can try to increase the postfix log level:

http://www.onlamp.com/pub/a/onlamp/2004/01/22/postfix.html

[andron26]

Thanks a lot.