Oddball DNS issue: won't resolve hostname alone.

Shane Hathaway shane at hathawaymix.org
Mon Dec 17 13:46:51 MST 2007


Charles Curley wrote:
> On Mon, Dec 17, 2007 at 10:52:45AM -0700, Shane Hathaway wrote:
>> Charles Curley wrote:
>>> I set up bind9 on an Ubuntu box several weeks ago. Now, email on two 
>>> Ubuntu machines is broken. I get, e.g.
>>>
>>> Dec 17 09:50:58 phoenix postfix/smtp[436]: 08D2A16A0E4:
>>> to=<ccurley at charlesc>, orig_to=<root>, relay=none, delay=8152,
>>> delays=8142/0.01/10/0, dsn=4.4.3, status=deferred (Host or domain
>>> name not found. Name service error for name=charlesc type=A: Host not
>>> found, try again)
>> This should work once "dig mx charlesc" works on 192.168.1.3.  Postfix
>> looks first for an MX record rather than an A record.
> 
> It does? I've never had an MX record before. And failing an MX record,
> shouldn't it then try for an A record?

No, it doesn't, which is counterintuitive but correct.  But I think I
understand: your mail server isn't public, so it's possible to configure
it with no MX record.

Clearly, Postfix is receiving the mail, but it thinks it needs to relay
the mail to some other server.  When it attempts to do so, it finds no
MX record for charlesc, so it generates an error.  You need to convince
Postfix that mail addressed to @charlesc is bound for this mail server,
not some other.

In main.cf (which is usually located in /etc/postfix) you need a
"mydestination" parameter that contains at least charlesc and
localdomain.  This is usually automatic; maybe your host/domain name
changed recently somehow.

I would put this line in main.cf and restart Postfix:

mydestination = charlesc, localhost, localdomain, charlesc.localdomain

Shane




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