SPAM question - General Internet Security question
 

Hello Guys,

I am posting in this forum because I don't realy know where else to post my question. Read, you will understand ;-)

I own a dommain, hosted on my own Linux server trough a cable connection.

I have a problem with my mail since I receive hundreds of non delivered mails witch I never sent.

I dig the maillog of PostFix (witch security is pretty tight) and I can't find traces of intrusion or any kind of relaying.

I know it is pretty simple to mangle the email header to set the FROM adress of the mail.

Now the real question is : Since the mail does not realy come from my dommain and only the FROM and RETURN adresses have been set to my dommain, is there any way I could avoid this ??

Here is a sample of non delivered message I receive:


Received: from unknown [82.177.36.10] (EHLO mail.gemappraisers.com)=> this is not my dommain ;-)

Any advise would be nice :-)

Thanks!

Everyone who manages a mail server has to deal with this crap. Some spammers use the return address as a way of getting mail through, since mail sent directly might more easily be recognized as spam.

We run sendmail with mimedefang, spamassassin, milter-greylist, procmail filters, . . . And we are constantly monitoring and tuning parameters in all of these to keep the spam out.

The level of spam is way up from last year, and way up from last spring. It just keeps escalating. You can probably blame it on all those zombies coming out of Redmond.