Name service error

classic Classic list List threaded Threaded
4 messages Options
Reply | Threaded
Open this post in threaded view
|

Name service error

Jeffrey Shawn Klotz-2
I'm having DNS issues when delivering mail on a postfix server.

The server seems to run fine for several hours.  

After a while, emails start to stay in the queue with the following error for all domains:

postqueue -p

D63998D18BF    88122 Thu Nov 13 20:19:58  [hidden email]
(Host or domain name not found. Name service error for name=att.blackberry.net type=MX: Host not found, try again)
                                         [hidden email]


If I flush the queue (postqueue -f) mail starts to flow again and continues to clear the queue for several hours.
The server does not seem to have DNS issues with other applications.  NSLookup does not seem to have issues.

I don't think it's a postfix problem.  Is there a way I can verify Postfix is able to perform DNS lookups?  Is there a way to log more detailed information on the routing/delivery process.

Thanks...

typical syslog entry:

Nov 13 20:21:19 email2 postfix/smtp[50936]: D63998D18BF: to=[hidden email], relay=none, delay=81, delays=0.02/0.02/81/0, dsn=4.4.3, status=deferred (Host or domain name not found. Name service error for name=att.blackberry.net type=MX: Host not found, try again)

Reply | Threaded
Open this post in threaded view
|

Re: Name service error

Sahil Tandon
Jeffrey Shawn Klotz <[hidden email]> wrote:

> I'm having DNS issues when delivering mail on a postfix server.
>
> The server seems to run fine for several hours.  
> After a while, emails start to stay in the queue with the following error
> for all domains:
>
> postqueue -p
>
> *D63998D18BF    88122 Thu Nov 13 20:19:58  [hidden email]
> (Host or domain name not found. Name service error for
> name=att.blackberry.net type=MX: Host not found, try again)
>                                         [hidden email]
> *
>
> If I flush the queue (postqueue -f) mail starts to flow again and continues
> to clear the queue for several hours.
> The server does not seem to have DNS issues with other applications.  
> NSLookup does not seem to have issues.

What if you nslookup as the postfix user?  What are the contents of your
/etc/resolv.conf?  What about /etc/nsswitch.conf or /etc/hosts?  See the
FAQ for clues: http://www.postfix.org/faq.html#delay.

> I don't think it's a postfix problem.  Is there a way I can verify Postfix
> is able to perform DNS lookups?  Is there a way to log more detailed
> information on the routing/delivery process.

Isn't it performing DNS lookups just fine when delivering to other
domains?  Is this problem limited to att.blackberry.net or was that just
one of many examples?  Also see:

http://www.postfix.org/DEBUG_README.html#mail.

--
Sahil Tandon <[hidden email]>
Reply | Threaded
Open this post in threaded view
|

Re: Name service error

Jeffrey Shawn Klotz-2
Sahil Tandon wrote:
Jeffrey Shawn Klotz [hidden email] wrote:

  
I'm having DNS issues when delivering mail on a postfix server.

The server seems to run fine for several hours.  
After a while, emails start to stay in the queue with the following error 
for all domains:

postqueue -p

*D63998D18BF    88122 Thu Nov 13 20:19:58  [hidden email]
(Host or domain name not found. Name service error for 
name=att.blackberry.net type=MX: Host not found, try again)
                                        [hidden email]
*

If I flush the queue (postqueue -f) mail starts to flow again and continues 
to clear the queue for several hours.
The server does not seem to have DNS issues with other applications.  
NSLookup does not seem to have issues.
    

What if you nslookup as the postfix user?  What are the contents of your
/etc/resolv.conf?  What about /etc/nsswitch.conf or /etc/hosts?  See the
FAQ for clues: http://www.postfix.org/faq.html#delay.

  
nslookup as user postfix works correctly.

resolv.conf contains:
domain example.com
nameserver 66.7.224.17
nameserver 66.7.224.18
nameserver 12.172.185.32
nameserver 12.172.185.34
nameserver 206.13.31.12
nameserver 12.127.17.71
nameserver 12.127.16.68
nameserver 12.127.17.72
nameserver 12.127.16.67

No nsswitch.conf on this system (OSX 10.5)

Hosts file contains only info on some local hosts.


  
I don't think it's a postfix problem.  Is there a way I can verify Postfix 
is able to perform DNS lookups?  Is there a way to log more detailed 
information on the routing/delivery process.
    

Isn't it performing DNS lookups just fine when delivering to other
domains?  Is this problem limited to att.blackberry.net or was that just
one of many examples?  Also see:

  
att.blackberry.net is only an example.  When the issue occurs, all domains have the same name service error.

http://www.postfix.org/DEBUG_README.html#mail.

  
At this point a cron job running postqueue -f  every few hours keeps the mail flowing.  That fixed the symptom but not the cause.  It's a bad solution, but it keeps mail flowing.

Thanks...


Reply | Threaded
Open this post in threaded view
|

Re: Name service error

Justin Piszcz


On Fri, 14 Nov 2008, Jeffrey Shawn Klotz wrote:

> Sahil Tandon wrote:
>> Jeffrey Shawn Klotz <[hidden email]> wrote:
>>
>>
>>> I'm having DNS issues when delivering mail on a postfix server.
>>>
>>> The server seems to run fine for several hours.  After a while, emails
>>> start to stay in the queue with the following error for all domains:
>>>
>>> postqueue -p
>>>
>>> *D63998D18BF    88122 Thu Nov 13 20:19:58  [hidden email]
>>> (Host or domain name not found. Name service error for
>>> name=att.blackberry.net type=MX: Host not found, try again)
>>>                                         [hidden email]
>>> *
>>>
>>> If I flush the queue (postqueue -f) mail starts to flow again and
>>> continues to clear the queue for several hours.
>>> The server does not seem to have DNS issues with other applications.
>>> NSLookup does not seem to have issues.
>>>
>>
>> What if you nslookup as the postfix user?  What are the contents of your
>> /etc/resolv.conf?  What about /etc/nsswitch.conf or /etc/hosts?  See the
>> FAQ for clues: http://www.postfix.org/faq.html#delay.
>>
>>
> nslookup as user postfix works correctly.
>
> resolv.conf contains:
> domain example.com
> nameserver 66.7.224.17
> nameserver 66.7.224.18
> nameserver 12.172.185.32
> nameserver 12.172.185.34
> nameserver 206.13.31.12
> nameserver 12.127.17.71
> nameserver 12.127.16.68
> nameserver 12.127.17.72
> nameserver 12.127.16.67
>
> No nsswitch.conf on this system (OSX 10.5)
>
> Hosts file contains only info on some local hosts.

For your /etc/resolv.conf file, only the first three matter:

        nameserver Name server IP address
               Internet address (in dot notation) of a  name  server  that  the
               resolver   should   query.    Up  to  MAXNS  (currently  3,  see
               <resolv.h>) name servers may be listed,  one  per  keyword.   If
               there are multiple servers, the resolver library queries them in
               the order listed.  If no nameserver  entries  are  present,  the
               default  is  to  use the name server on the local machine.  (The
               algorithm used is to try a name server, and if the  query  times
               out, try the next, until out of name servers, then repeat trying
               all the name servers until  a  maximum  number  of  retries  are
               made.)