[CentOS] Sendmail and pmtu discovery

Kai Schaetzl wrote:
> Sean Carolan wrote on Tue, 14 Oct 2008 08:13:34 -0500:
>
>> My mail logs are showing that customers who specifically disallow ICMP
>> traffic have many "Connection Reset" entries in our logs:
>
> Could somebody explain why ICMP might play a role in mail delivery?

It doesn't really. If the OP had PMTU discovery turned on it
would affect most all communications not just email. I can't
ever remember having it on for external networks, there's
never been a need in my case.

It's just likely that the only communications between the OP's
systems and the other side was email.

nate