On Thu, Jul 21, 2011 at 06:39:58PM +0000, Eric Smith wrote:
> Hi All,
>
> Here is a strange issue, incoming mail for yahoo fails roughly every 10th
> time. Also this is (reportedly) only happening to yahoo emails, all other
> email domains come through just fine.
>
> The setup is on ubuntu 10.4 LTS with the standard packages, postfix, clamav,
> amavis and spamassassin.
>
> I have tried many different solutions, TCP_window size is set to 64, 300 smtp
> process's is the limit, the system is not being overloaded. I also have
> worked with Sonicwall to make sure that the TCP packets are not getting
> munged.
>
> Any thoughts?
You have failed to describe the problem.
> Failed connection:
>
> Jul 21 09:15:55 loki postfix/smtpd[23510]: connect from
> nm1-vm0.bullet.mail.ne1.yahoo.com[98.138.91.74]
> Jul 21 09:15:55 loki postfix/smtpd[23510]: match_hostname:
> nm1-vm0.bullet.mail.ne1.yahoo.com ~? 192.168.1.0/24
Why is verbose logging enabled, turn it off.
> Jul 21 09:15:55 loki postfix/smtpd[23510]: >
> nm1-vm0.bullet.mail.ne1.yahoo.com[98.138.91.74]: 220 mail.techsoft3d.com
> ESMTP Postfix
> Jul 21 09:15:55 loki postfix/smtpd[23510]: smtp_get: EOF
Yahoo dropped the connection, probably before you even accepted it. With
verbose logging slowing down your server, it may take too long from TCP
3-way handshake until a Postfix smtpd is ready to process it.
> Jul 21 09:15:55 loki postfix/smtpd[23510]: lost connection after CONNECT from
> nm1-vm0.bullet.mail.ne1.yahoo.com[98.138.91.74]
> Jul 21 09:15:55 loki postfix/smtpd[23510]: disconnect from
> nm1-vm0.bullet.mail.ne1.yahoo.com[98.138.91.74]
First turn off verbose logging. Then make sure your syslog is not
doing synchronous writes to disk for every log message. Then see whether
you still have a problem.
Yahoo is timing out you server. Perhaps your DNS is also slow.
--
Viktor.
