Hello George,
As far as I know, there is no really clean way. However, the following
(implemented in our autoresponder utility for answering user inquiries
and our newsgroup gateway) approach may work for you:
have a on disk hash table that records the 'user' part of 'user@domain'
and time. Now, for each delivery, a check is performed to ensure that
'user@domain' doesn't have more than x number of messages in y seconds.
If the limit is exceeded, the sender gets a bounce with warning.
So, basically this is a throttle. It should give some relief
to your situation.
Regards,
Chin Fang
[EMAIL PROTECTED]
> Hello,
>
> Yesterday, I came up to a strange situation:
> I was receiving thousands of bounces to
> <a lot of different usernames>@<mydomain>.
> Since <mydomain> is in my rcpthosts/locals file, I was accepting these
> messages. But <a lot of different usernames> didn't exist so these
> messages were going to postmaster.
> My mailserver had a lot of traffic, its logfiles were very large and the
> mailbox of postmaster become unreadable.
>
> Is there any way to prevent my mail servers from these types of attack?
>
> Thanks for your time,
> George Stathakopoulos
>
>
