Vick Khera:
> I had a huge backlog to cox.net the other day on one of my servers.
> Their postmaster gave me the following issues they observed with us,
> which caused them to temporarily block the server:
>
> 1. Your mailserver is attempting to communicate too soon within the
> SMTP transaction. Ensure that your sending server is RFC
> 5321-compliant, and is following the proper SMTP protocol standards.
Amazingly, for the past two years Postfix has come with a feature
called postscreen that drops SMTP clients that speak to soon. I am
100% certain that Postfix never makes that error itself.
> 2. Your mailserver is attempting to send more than 100 messages in one
> session.
> As for item 2, the only limit postfix allows me to set is the time
> that the connection will be reused. The default 300s seems too large
> for them. How can I approximate the 100 delivery limit using time? I
> set it to 30s for now and will see if we block with them again.
Just don't reuse connections when sending mail to sites with
weird limitations.
/etc/postfix/transport:
example.com smtp_no_reuse:
/etc/postfix/master.cf:
smtp_no_reuse unix - - n - - smtp
-o smtp_connection_cache_on_demand=no
Wietse
