[olug] disable the default search domain?

[Rob Townley]

On Thu, Dec 11, 2008 at 1:04 PM, Ryan Stille <ryan at cfwebtools.com> wrote:
> We have a DNS wildcard here.  This is affecting my sendmail box.  When
> it tries to send mail to an invalid domain, such as foox123.com, the DNS
> lookup initially fails, but then it tries foox123.com.mydomain.com and
> it gets back an IP (because of the dns wildcard).   So the message says
> in the queue for days while it tries to deliver that message to a server
> that's not a mail server.
>
> To be clear - I don't have any "search x" lines in my resolv.conf file.
> Its happening because the machine's domain name is a search domain by
> default.   I haven't found a way to disable this, other than to change
> the hostname to be "machinename" instead of "machinename.mydomain.com".
> I'm not sure what else that might screw up.  Any ideas?
>
> -Ryan
>
>
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There is a sendmail config option "fundamentally incompatible with
wildcard MX records."

Best MX is Local
----------------
If enabled, this option will cause sendmail to accept mail as though locally
addressed for any host that lists this machine as the best possible MX record.
This generates additional DNS traffic, but should be OK for low-to-medium
traffic hosts. N.B.: This feature is fundamentally incompatible with wildcard
MX records. If you have a wildcard MX record that matches your domain, you
cannot use this feature.

Assume best MX is local? [N]

accept_unresolvable_domains

i came across the following for a different wildcard problem, but i
would probably be useful.
http://en.wikipedia.org/wiki/Wildcard_DNS_record