How can I prevent my server from crashing in a DOS attack??
Hello, I was getting thousands of emails from another server attempting to relay these messages. As it was explained to me in the post below the zimbra email digests email in postfix>amavis>postfix>mailbox order.
The 10000 emails trying to be relayed seem to have either been sitting in the que and trying to get resent because even after I blocked all traffic incoming or outgoing to my server zimbra was trying to resend them.
How can I have postfix analyse the incoming emails and check the heading and see if in fact they are trying to get relayed from an invalid local domain and discard them right from the beggining instead of passing the email to amavis and then to postfix and ultimately bringing down the server. I know there's a way because I have set up another server until I get this fixed instead of zimbra with the same amount of traffic trying to be relayed through my other server and it discards the email right from the beggining..
I need to know how to do this because blocking a segment of ip's is really unpractical and in the future I want to be able to prevent no matter where it comes from.
Thanks very much.