New ways for email DoS

[Stathakopoulos Giorgos]

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

Authenticate with From: header...

[Stathakopoulos Giorgos]

I want my users not to be able to send mail through my server and set
their "From:" header to whatever they want.

Is there any simple way to restrict relaying to users that authenticate
themselves using the "From:" header?

Another way might be to change "From:" header at the server, respectively
to the username that authenticated.

Any ideas are welcome...

Thanks,
G.Stathakopoulos

WARNING: double delivery

[Stathakopoulos Giorgos]

Does anyone know why is this happening?


Jun 22 18:40:58 machine qmail: 930066058.357501 warning: trouble marking
remote/2/59434; message will be delivered twice!
Jun 22 18:40:58 machine qmail: 930066058.357787 warning: unable to unlink
remote/2/59434; will try again later

Thanx,
G.Stathakopoulos

Different logs for different domains

[Stathakopoulos Giorgos]

Our server is MX for 3 different domains. Is there any way to log qmail
info in 3 different log files? Is there any way to log this info (with
syslog.conf) to even 3 different hosts?

G.