Host lookup failure with Sendmail
I have a problem with sending mail from my fileserver (named Arkiv, for LAN access only) to my mailserver (named Post, in a DMZ). I basically only want to do this to aggregate my logcheck, etc mails in one mailbox, that is also accessible from the outside.
The fileserver is separated from the mailserver by a firewall where only sendmail connections orginating from the fileserver are allowed through (as well as ssh). The fileserver is not allowed any direct contact with the Internet.
Sending mail locally between users on the fileserver works fine and when I try to "telnet post 25" to the mailserver I can manually send mail through.
The problems start when I try to send an mail in any other way between the boxes. I then get the message accepted for delivery but then the host name resolve fails for some reason.
In var/log/maillog the attemted mail submission looks like this:
Sep 29 12:18:43 arkiv sendmail: i8TAGgrX026048: from=<email@example.com>, size=243, class=0, nrcpts=1, msgid=<Pine.LNX.firstname.lastname@example.org>, proto=ESMTP, relay=root@localhost
Sep 29 12:18:43 arkiv sm-mta: i8TAIh3h026051: from=<email@example.com>, size=436, class=0, nrcpts=1, msgid=<Pine.LNX.firstname.lastname@example.org>, proto=ESMTP, daemon=MTA, relay=localhost [127.0.0.1]
Sep 29 12:18:43 arkiv sm-mta: i8TAIh3h026051: to=<email@example.com>, ctladdr=<firstname.lastname@example.org> (0/0), delay=00:00:00, xdelay=00:00:00, mailer=esmtp, pri=30436, relay=post.comba-telecom.se., dsn=4.0.0, stat=Deferred: Name server: post.comba-telecom.se.: host name lookup failure
Sep 29 12:18:43 arkiv sendmail: i8TAGgrX026048: to=<mattias@post>, ctladdr=<email@example.com> (0/0), delay=00:00:00, xdelay=00:00:00, mailer=relay, pri=30243, relay=[127.0.0.1] [127.0.0.1], dsn=2.0.0, stat=Sent (i8TAIh3h026051 Message accepted for delivery)
Since I use my ISPs DNS, I have used /etc/hosts as a DNS for my system so far with no problem. I have not run into problems with resolving the relationship with Arkiv and Post before.
The /etc/hosts file looks like this
# For loopbacking.
192.168.11.101 arkiv.comba-telecom.se arkiv
192.168.12.2 post.comba-telecom.se post
192.168.1.1 grind.comba-telecom.se grind
# End of hosts.
I'm using the standard sendmail.cf and submit.cf on a Slackware 9.1 platform.
Any help is appreciated.