Hi !!
> I will just throw in a non-SMTP solution here
>
> If you treat this sudden peak in traffic hitting your servers as a DDOS to
> your infrastructure then the best place to stop it is at the ingress to your
> network. So you have the firewall do one or more of a number of things
>
> Limit the number of concurrent SMTP sessions fro anywhere to your mail
> servers
> Limit the number of new SMTP sessions per second
> Limit the number of SMTP sessions from a single IP
> Limit the amount of bandwidth SMTP can consume on the network
exim can done most of this itself, also we use a cdb based white/blacklist
at smtp_connect so we can delay non-whitelisted hosts on peak times
and accept mail comming from whitelisted ones. On a really bad situation
this allows to get mail working (at least for whitelisted hosts) and
fast reject anything else
--
Best regards ...
The brain you have reached is out of order at this time.
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