Problems with emails being deferred

[nicholas00]

i have problems with emails sending out to outside people.
example: john@mydomain.com sends mail
to: david@notmydomain.com
cc: peter@mydomain.com

peter receives the email but david receives it hours or probably days later.

when i do a postqueue -p this is what i get

7DC0856D01CE 23208 Mon Jun 2 10:29:24 john@mydomain.com
(Host or domain name not found. Name service error for name=notmydomain.com type=MX: Host not found, try again)
david@notmydomain.com

i believe it has something to do with the MX records but i cant find any solutions in the internet for it.

i am currently using zimbra version 4.0.5
the mail server also has its own DNS

and i end up having 200 over mails stuck in deferred queue.

[phoenix]

From the error message it would appear that the mail server at 'notmydomain.com' has a problem with MX resolution. You can check it's DNS records by going to Pingability.com: Web Site Monitoring and Alert Service and running a check on their domain name. You can also check it from the Zimbra server by doing the following:

dig notmydomain.com mx
dig notmydomain.com any

and see if that has any problems.

[nicholas00]

From the error message it would appear that the mail server at 'notmydomain.com' has a problem with MX resolution. You can check it's DNS records by going to Pingability.com: Web Site Monitoring and Alert Service and running a check on their domain name. You can also check it from the Zimbra server by doing the following:

dig notmydomain.com mx
dig notmydomain.com any

and see if that has any problems.

Thx for the reply

the problem is not just with notmydomain.com, i also had the same error with a lot of other domain.

i tried dig

notmydomain.com any

its returns me connection time out but when i use my own pc to ping notmydomain.com, it has no errors.

i am suspecting the problem lies with my DNS, but it has been working fine for last few years till now.

[phoenix]

i am suspecting the problem lies with my DNS, but it has been working fine for last few years till now.

That would be the most likely explanation. What's in your resolv.conf, are you using any upstream DNS servers as well as your own? Is your DNS a forwarder (to your ISP, for instance) or does it resolve using root servers? Could there be a firewall problem on your LAN?

try the following:

dig @212.27.53.252 notmydomain.com any

Does that get a better (or any) response?

[nicholas00]

That would be the most likely explanation. What's in your resolv.conf, are you using any upstream DNS servers as well as your own? Is your DNS a forwarder (to your ISP, for instance) or does it resolve using root servers? Could there be a firewall problem on your LAN?

try the following:

dig @212.27.53.252 notmydomain.com any

Does that get a better (or any) response?

in my resolv.conf:

 
domain mydomain.com
nameserver 127.0.0.1

dig @212.27.53.252 notmydomain.com any

still give me connection time out.

instead when i dig the ip address, it has no errors.

will be resolving the problem myself.

Problem might be due to dns forwarder. As it is currently pointing to my other DNS server which might be the problem.

thanks for all the help.