postfix reverse dns lookup problem

[miks]

Postfix doesn't resolve reverse DNS to any incoming connections.

from maillog:

postfix/smtpd[92531]: connect from unknown[74.125.83.48]

doing reverse name lookup on this server:

#host 74.125.83.48
48.83.125.74.in-addr.arpa domain name pointer mail-gw0-f48.google.com.

Already googled, but found no solution to my problem.
Any suggestions?

 

[ohauer]

I guess the lookup from postfix was running in a timeout or the response was to slow.
Set up a small caching dns (bind/djbdns) on the mailserver helps a lot and a lot more if you are using RBL lists.

 

[miks]

Found out that postfix was running chroot as configured in master.cf
Changed to non-chroot and reverse dns records now is resolving correctly.
Anyway I don't understand why it's wasn't working with chroot flag set to "Y"

 

[ohauer]

Anyway I don't understand why it's wasn't working with chroot flag set to "Y"

Because some files where missing for the chrooted daemons.

If you have only one instance of postfix (not multi instances) you can solve this by

umask 022
mkdir /var/spool/postfix/etc
chmod 755 /var/spool/postfix/etc
cd /etc ; cp host.conf localtime services resolv.conf /var/spool/postfix/etc

Hint: this is explained in the old postfix faq or if you extract the source tarball in the directory examples/chroot-setup