Wietse Venema: > Martin Vegter: > > Hello, > > > > I have noticed that my Postfix never resolves client IP Addresses into > > hostnames. In the logs I have always entries like the following: > > > > connect from unknown[173.194.40.54] > > > > I can resolve the IP manually into FQDN, using dig or host commands: > > > > host 173.194.40.54 > > > > So any DNS misconfiguration on my server is ruled out. > > Postfix will ignore the name if it does not resolve to the client > IP address (it will also log a warning to that effect). > > > Do I ned to change any settings in postfix, so that client IPs are > > resolved into hostnames? > > You need the correct DNS server in /etc/resolv.conf.
That file must be world-readable (mode 644) and the / and /etc directories must allow search permission (mode 755). Depending in your OS this also applies to /etc/nsswitch.conf and files referenced by it, as well as their parent directories. > You must not have "disable_dns_lookups=yes" in main.cf or master.cf. > > You must not have "smtpd_peername_lookup=no" in main.cf or master.cf. > > You may also need to turn off chroot per instructions in > http://www.postfix.org/DEBUG_README.html#no_chroot > > Wietse >
