[Web-cyradm] HOW TO: Rejecting Unknown Local Recipients ??

[Stuart Murray-Smith]

>  I need some help.
>  Right now we are using greylisting / spamassasin / antivirus and so on,
> but, now spammer are gentting really more "smart":
>  if a spammer use a real SMTP bypass the greylist, and if the mail is well
> formatted it may by-pass also the spamassasin.
>  It's quite normal, but the point is, if a large number of email are send to
> a non existing user these email are processed and only at the end a mail
> form MAILER DEAMON is send for a not existing user... so a lot of mail, more
> than 2500 in some server a day, are processed... and in some case the queue
> is really overloaded.

Hi Andrea

Yes, we're experiencing this too. I think this phenomenon is known as
'backscatter'. See:

http://www.postfix.org/BACKSCATTER_README.html

and

http://www.hispalinux.es/~data/postfix/

HTH

Have a great day!

Stuart



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