SMTP problems: Host not found, try again

[gboyce-qL0WqcyiFk9Wk0Htik3J/w at public.gmane.org (Gregory Boyce)]

On Tue, 2 Jun 2009, david-8uUts6sDVDvs2Lz0fTdYFQ at public.gmane.org wrote:

> So I'm kinda sorta close to finishing my server rebuild, but I'm still
> having issues.  One I would like to get solved asap is this SMTP issue.
> This is Ubuntu Jaunty with postfix/dovecot.
>
> I see messages like this very frequently (email addresses redacted) in the
> logs and the output of postqueue -p:
> 813404C5F7     2130 Tue Jun  2 03:47:36
> particularization9-qIPW8QmpbdTTeotY1rLAZGXnswh1EIUO at public.gmane.org
> (delivery temporarily suspended: Host or domain name not found. Name
> service error for name=comcast.net type=MX: Host not found, try again)
>                                         XXXXX-Wuw85uim5zDR7s880joybQ at public.gmane.org
>
> 809EE461A7     8687 Mon Jun  1 12:05:35  avengesp616-sdv56KyyKd+sTnJN9+BGXg at public.gmane.org
> (delivery temporarily suspended: Host or domain name not found. Name
> service error for name=acm.org type=MX: Host not found, try again)
>                                         XXXXX-HInyCGIudOg at public.gmane.org
>
> and a bunch of other domains.
>
> "digg acm.org mx" returns the list of MX servers.
> I can telnet to one or more of the XM servers on port 25.

I'm guessing you're getting hit by temporary DNS resolution failures.  Do 
you run your own nameserver or using your ISPs NS?  If you're using your 
ISPs NS, I'd suggest installing bind as a local resolver or try switching 
to UltraDNS's nameservers to see if that helps.

--
Greg