[Lilux-help] postfix & spam handling

Hello Folks, a mailserver we administer is currently under heavy attack by spam, that is, we get *tons* (100+/second) of messages to addresses like johndoe(a)mydomain.lu. This mailbox johndoe of course does not exist. Here an extract of the log: Nov 1 19:55:53 roma postfix/virtual[21113]: 780104B0E7: to=&lt;root(a)mydomain.lu&gt;, orig_to=<postmaster@localhost>, relay=virtual, delay=341690, status=SOFTBOUNCE (unknown user: &quot;root(a)mydomain.lu&quot;) Some how it seems the send message remains in one of the postfix queues, and causes a general slowdown of mail handling of the server. I just want it to drop these (anyway) undeliverable messages, but fail to set this up... The main.cf is attached. Help is appreciated... / me desperate ... :-| regards, Yves p.s. I am not an expert with postfix, the mailserver runs fine since 6 month. The mentioned problems started 3 days ago only. -- Linux 2.6.17-10-generic #2 SMP Fri Oct 13 18:45:35 UTC 2006 i686 19:54:01 up 1:07, 1 user, load average: 0.11, 0.09, 0.07