bind/sendmail resolving.. (NXDOMAIN)

[Kevin Darcy]

"host" performs A, AAAA and MX queries, by default. If you want to limit 
it to a specific query type, use the "-t" option.

Having said that, I didn't get an NXDOMAIN for any of the query types, 
from any of the delegated nameservers, when using dig, but I'm getting 
SERVFAILs when using host, *after* the initial A-record query (as seen 
in debug mode). I'm not that familiar with "host" to be able to 
troubleshoot this very easily. The 0-second-TTL on the record probably 
isn't helping. It seems likely (rad = Radware, probably) that it's 
actually load-balancing devices answering these queries, rather than 
actual nameservers.

Last but not least, it's not legal to point an MX record at an *alias*, 
and that's probably the root cause of your main problem (sendmail 
failures) here...

                                     - Kevin

On 9/20/2013 6:51 PM, Howard Leadmon wrote:
>    This is probably easier than I am making it, but my googlefu seems to be
> failing me at the moment when I look around.   I  handle a batch of FreeBSD
> servers running sendmail, and I am having a site that is trying to deliver
> mail being rejected, but they swear their DNS is right, so I am not sure if
> we have an issue, or they do.
>
>   I am seeing sendmail rejects like this:
>
> Sep 20 14:45:59 mail3 mail3-smtp[15388]: r8JE8kQg099367:
> to=<jmeteyard at panini.co.uk>, delay=1+04:37:10, xdelay=00:00:31,
> mailer=esmtp, pri=5259883, relay=smtp2.panini.co.uk., dsn=4.0.0,
> stat=Deferred: Name server: smtp2.panini.co.uk.: host name lookup failure
>
>
>   If I take and run a host lookup, I get a response like this:
>
> $ host panini.co.uk
> panini.co.uk mail is handled by 10 smtp.panini.co.uk.
> panini.co.uk mail is handled by 20 smtp2.panini.co.uk.
>
>
> Now if I try that on any of the hosts that should accept the mail, I see:
>
> $ host smtp.panini.co.uk
> smtp.panini.co.uk is an alias for smtp.panini.it.
> smtp.panini.it has address 151.12.160.24
> Host smtp.panini.it not found: 3(NXDOMAIN)
>
> $ host smtp2.panini.co.uk
> smtp2.panini.co.uk is an alias for smtp2.panini.it.
> smtp2.panini.it has address 151.12.160.30
> Host smtp2.panini.it not found: 3(NXDOMAIN)
>
>
>   So I get the IP address returned, but then an NXDOMAIN that follows.   I do
> have the BrokenAAAA config option in my sendmail, so know it's not that, or
> I don't think so.    Yet if I do a dig on the hosts, they seem to come back
> with an IP address as expected, and shown above.
>
>   So if anyone can offer a clue on this, it would be appreciated..
>
>
> ---
> Howard Leadmon
>
>
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