I'm getting bounces from one service provider and I'm not sure what the problem is or how to fix it. It seems like it's looking for some kind of reverse DNS (reverse DNS is set up for our domain) or it's objecting to the hostname?? I'm not a quite a noob but am a bit fuzzy on some of these concepts and I'm not sure what the right direction to take to eliminate these bounces is.


Here's the bounce message...
This is the mail system at host li52-167.localdomain.

I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.

For further assistance, please send mail to postmaster.

If you do so, please include this problem report. You can
delete your own text from the attached returned message.

The mail system

<xxxx@optonline.net>: host mx1.optonline.net[167.206.4.77] said: 550 5.7.1 We
do not accept mail from dynamic-IP hosts or generic/machine-generated
hostnames - you must get a custom reverse-DNS name from your ISP for your
host: li52-167.localdomain: xxxx@optonline.net (in reply to RCPT TO
command)
Reporting-MTA: dns; li52-167.localdomain
X-Postfix-Queue-ID: ACAF02120D
X-Postfix-Sender: rfc822; xxxx@mydomain.com
Arrival-Date: Fri, 1 May 2009 13:15:21 -0400 (EDT)

Final-Recipient: rfc822; xxxx@optonline.net
Original-Recipient: rfc822; xxxx@optonline.net
Action: failed
Status: 5.7.1
Remote-MTA: dns; mx1.optonline.net
Diagnostic-Code: smtp; 550 5.7.1 We do not accept mail from dynamic-IP hosts or
generic/machine-generated hostnames - you must get a custom reverse-DNS
name from your ISP for your host: li52-167.localdomain: xxxx@optonline.net

setup your reverse dns. if you go into the linode manager, it's in the "linodes" tab, click your linode, then in the "network" tab you'll find the place to setup reverse dns for your linode.

_________________
http://ultramookie.com/

Umm.....

Have you set your mailname (/etc/mailname, or as defined within exim/postfix), and/or your server hostname ?

Did you set it to li52-167.localdomain?

If so, try to use something that looks less like a machine-generated name.

If not, then figure out why the reporting MTA thinks you did. Try "dig -x" on the ip address of your server and see what you get.