[Mailman-Users] emails from mailman rejected with error "reject=550 Relaying denied. IP name possibly forged"

[Stephen J. Turnbull]

Abdullah Maskari writes:

 > Jul 24 09:09:16 mailhost sm-mta[3309]: s6O89FAL003309:
 > ruleset=check_rcpt, arg1=<target-address at external.domain2.com>,
 > relay=mailhost.server.in-dmz.on.internal-domain.com [mailhost ip
 > address] (may be forged), reject=550 5.7.1
 > <target-address at external.domain2.com>... Relaying denied. IP name
 > possibly forged [mailhost ip address]

Looks to me like your DNS is quite broken (the references to IP
addresses being forged).  Many destination hosts will filter such
mail.

The enhanced status code is 5.7.1, an administrative reject.  You've
violated somebody's spam-filtering policy, and they're not accepting
mail from you.  You might want to check if your IP address(es) are on
a blackhole list.

However, I think the immediate priority is fixing your DNS so that
your external mail server is the MX for your domain, which has a
proper A and/or AAAA address (ie, the domain name advertised is not a
CNAME), and has PTR record from the MX name to the server's IP.