Help - Name server timeout

[Will Yardley]

Barry Margolin wrote:
> Will Yardley  <william+dns at hq.newdream.net> wrote:

> >there is no A record for that domain.  i believe that sendmail by default
> >won't send mail to, or receive mail from, domains that don't have an A record
> >that resolves.
 
> You seem to have completely forgotten about MX records.  One of the reasons
> MX records were created was to allow mailing to addresses that aren't on
> the Internet, and therefore don't have A records.

no - i haven't forgotten about MX records.  however some versions of
sendmail (especially more recent ones such as the version used by the
person who wrote in) do checks to see if a hostname resolves
cannonically by default - if you don't want sendmail to perform these
checks you have to add stuff to the sendmail configuration file.  for
instance some versions of sendmail will refuse mail from a domain that
doesn't have an A record (even if there's an MX record), and the same
for sending mail (or at least that's my understanding).  This is why
there are options like 'Accept_unresolvable_domains'.  There are also
some problems in 8.12 if sendmail gets the wrong kind of response for an
aaaa record if sendmail is configured for ipv6

for instance i was having problems with sendmail 8.12 beta and the
domain 'prodigy.net.mx'.  there is a 'servfail' response when asking for
an aaaa record instead of an empty response with an soa record.

this seems to cause problems with the cannonification process in
some versions of sendmail.

w

-- 
Sintax error in config file! (line 378)
aborted!