Hi,
a question about a configuration detail:
I have a server machine providing services for several
users (each with one or more DNS domains) with the virtual domain
alias mechanism.
Some users have several domains, but do configure their
mail recipients for their primary domain only, and simply
map their other domains onto their primary, e.g.
john AT domainA DOT de john AT somewhereelse DOT de
jane AT domainA DOT de jane AT somewhereelse DOT de
@domainB.de @domainA.de
If a spammer sends mail to xxx AT domainA DOT de postfix
immediately rejects this message, because smtpd's lookup
mechanism detects that there is no entry for xxx AT domainA DOT de.
Message is not accepted, no bounce message generated.
But if a spammer sends to xxx AT domainB DOT de, postfix accepts
this message because smtpd does not recurse and just performs
a simple first step lookup. The delivery daemon then maps this
onto xxx AT domainA DOT de and then detects that there is no such
recipient and produces a bounce messages, which in case of
Spam is usually sent to a wrong sender, since Spam uses
fake sender addresses.
These bounce messages are causing us some headache.
Is there a way to turn full recursion for the smtpd at
recipient time on to detect that these addresses do not
exist?
regards
Hadmut
|
