Kadlecsik József wrote:
Hello,
One of our users reported a rejected email with the error code and message
Remote-MTA: dns; artemis.gat.com
Diagnostic-Code: smtp; 550 Sender IP reverse lookup rejected
We handle several domains with different outgoing smtp settings at
multiple mail gateways:
# /etc/postfix/master.cf
wignersmtp unix - - y - - smtp
-o smtp_bind_address=148.6.0.56
-o smtp_bind_address6=2001:738:5001::56
Slightly wild guess: Something about the reverse DNS entries bothers
the receiving site. (Whether it's a reasonable complaint is something
else entirely, and rejecting mail to postmaster@ is not very bright all
on its own.)
kdeugau@pod:~$ host 148.6.0.56
56.0.6.148.in-addr.arpa domain name pointer smtp.wigner.mta.hu.
kdeugau@pod:~$ host smtp.wigner.mta.hu.
smtp.wigner.mta.hu has address 148.6.0.58
smtp.wigner.mta.hu has address 148.6.0.56
smtp.wigner.mta.hu has address 148.6.0.57
smtp.wigner.mta.hu has IPv6 address 2001:738:5001::56
smtp.wigner.mta.hu has IPv6 address 2001:738:5001::57
smtp.wigner.mta.hu has IPv6 address 2001:738:5001::58
I would recommend giving each of those IPs a unique PTR name, and
setting up matching A or AAAA records.
I'm guessing they're erroring on either the multiple IPs in the forward
lookup, or the mismatch between PTR and at least one forward entry.
They may still fail if you have eg:
56.0.6.148.in-addr.arpa domain name pointer smtp1.wigner.mta.hu.
smtp1.wigner.mta.hu has address 148.6.0.56
smtp1.wigner.mta.hu has IPv6 address 2001:738:5001::56
-kgd
