Visit Jeremy's Blog.
Go Back > Forums > Linux Forums > Linux - Distributions > Slackware
User Name
Slackware This Forum is for the discussion of Slackware Linux.


  Search this Thread
Old 09-29-2004, 06:29 AM   #1
LQ Newbie
Registered: Jun 2004
Posts: 3

Rep: Reputation: 0
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[26048]: i8TAGgrX026048: from=<>, size=243, class=0, nrcpts=1, msgid=<>, proto=ESMTP, relay=root@localhost

Sep 29 12:18:43 arkiv sm-mta[26051]: i8TAIh3h026051: from=<>, size=436, class=0, nrcpts=1, msgid=<>, proto=ESMTP, daemon=MTA, relay=localhost []

Sep 29 12:18:43 arkiv sm-mta[26053]: i8TAIh3h026051: to=<>, ctladdr=<> (0/0), delay=00:00:00, xdelay=00:00:00, mailer=esmtp, pri=30436,, dsn=4.0.0, stat=Deferred: Name server: host name lookup failure

Sep 29 12:18:43 arkiv sendmail[26050]: i8TAGgrX026048: to=<mattias@post>, ctladdr=<> (0/0), delay=00:00:00, xdelay=00:00:00, mailer=relay, pri=30243, relay=[] [], 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. localhost arkiv post grind
# End of hosts.

I'm using the standard and on a Slackware 9.1 platform.

Any help is appreciated.

Old 09-30-2004, 08:52 AM   #2
LQ Newbie
Registered: Nov 2003
Location: Germany
Distribution: Slackware 7.0 - 10.0
Posts: 26

Rep: Reputation: 15
Looks like you need a MX entry for your mail server as long as you use ISP DNS it won't work sorry.
Old 09-30-2004, 09:15 AM   #3
LQ Newbie
Registered: Sep 2004
Location: Eastern Pennsylvania, US
Distribution: Slackware
Posts: 21

Rep: Reputation: 15
Take a look at this and see if it helps you:

In particular, run that dig command on your arkiv system and see what it turns up.

Oh, and as the author says, his mailertable fix only solves the problem locally, but that might be all you need.

Old 09-30-2004, 10:47 AM   #4
LQ Newbie
Registered: Jun 2004
Posts: 3

Original Poster
Rep: Reputation: 0
Thanks for the help!

It solved the problem. Although it takes sometime for the mailsubmission to go through (approx 30s). I'm assuming it tries to resolve for an MX record before giving up and submitting anyway...

Is this to be the way to get sendmail to work between computers on a network without having to set up a fully fledged DNS service with MX records, etc. Or is there an alternative solution?


Last edited by MattiasLofgren; 09-30-2004 at 11:36 AM.
Old 05-14-2009, 04:00 PM   #5
LQ Newbie
Registered: May 2009
Location: Seattle, Wa.
Distribution: Slackware
Posts: 3

Rep: Reputation: 0
Should this mailertable contain the host I am using? or the host that keeps bouncing mail back with Hostname lookup failure? I have about 6 ip's that bounce mail back with either hostname lookup failure, or Timeout exceeded. All other ip's can send mail just fine. I use sendmail on slackware 12.2 and earthlink and as well as keep bouncing my mail back with these errors. I run through a motorola router (DSL) and just can't seem to figure out how to send email to these certain ip's. They can send email into me, but I can't send to them. Is there anything I can do to fix this?

Last edited by mirader9813; 05-14-2009 at 04:08 PM. Reason: add more info


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Telnet : Temporary failure in name resolution : Host name lookup failure koodoo Linux - Newbie 10 02-11-2008 08:59 PM
Host name lookup failure mauroblanc Linux - Networking 2 06-16-2005 03:09 PM
DHCP: Host name lookup failure kaloyer *BSD 2 07-08-2004 12:01 PM
sendmail: host name lookup failure GabeF Linux - Networking 3 12-04-2002 09:00 AM
getting an error name lookup failure udayan Programming 2 08-23-2002 12:23 AM > Forums > Linux Forums > Linux - Distributions > Slackware

All times are GMT -5. The time now is 11:04 PM.

Main Menu
Write for LQ is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
Facebook: linuxquestions Google+: linuxquestions
Open Source Consulting | Domain Registration