Christian Hattemer wrote:
[ ... ]
> I'm going to tell the ISP about the misconfiguration. But I'd like to have a
> purely local fix for the issue, in case they (or another ISP I might change
> to) break it again. Is this possible? Perhaps get sendmail not to do DNS
> queries for local mail at all, or perhaps a local nameserver?

You can set up a local nameserver, which is a good idea if your ISP doesn't 
promptly fix any problems on their end.  You can also tell sendmail not to do 
DNS queries by using:

	FEATURE(nocanonify)

...in your sendmail.mc file.  In that case, you should also define a SMART_HOST 
by IP address, and point it towards your ISP's SMTP server, who will handle the 
DNS lookups for you.

Of course, none of the above will help get mail out of /var/spool/clientmqueue.
If that is still a problem, you need to run a MSA queue runner via:

	sendmail -L clientmqueue-runner -Ac -q30m

...as I mentioned before.

-- 
-Chuck