Re: [Exim] Under attack: discarding mail.

> Now some "@@@@@"fellow is spamming to some [invalid]
> address giving as sender random usernames in one of my hosts.
> This led to this annoying effect, that is a lot of frozen message ....
> Any idea on avoiding this ?

A frozen message usually indicates that you have a serious configuration
problem, that should be fixed. I can only guess why sending messages
with empty sender and unknown local part freezes the message: Perhaps
the message verifies ok, but the transport fails? Try running exim with
option -bh and the IP of the originating host as well as debugging, and
you will see exactly how it verifies addresses and directs the message.

> (i do not think just accepting and forwarding to bit_bucket ANY
> message sent to unknown locar user is a good idea, since it could
> give the appearence that the users are really here !)

Correct. I heard of dictionary attacks to find valid mail addresses
from a postmaster at another site. Guess how happy people were who
forward mail to all local parts inside a domain to their mailbox...

Michael