HELP Mail Exchange Resolution

  • Thread starter Thread starter Jason
  • Start date Start date
J

Jason

We are having trouble with resolving a DNS entry for another companies Mail
Server. Very strange situation hopefully someone can help me with this one.

From what I can tell this other company has two MX entries in their DNS one
withpriority of 10 the other with priority of 5. The server that we need to
be sending the mail to is set to priority of 5. If I do an nslookup I get
from the cache the 10 entry. So I go to the DNS Server and clear the cache.
Then do an nslookup I get both addresses the 5 and 10. Then send the mail
again the 5 disappears and the 10 remains. The mail times out looking for
the server and does not get delivered. So I go in and clear the cache again
do a new lookup and get both MX records again. I delete the 10 record
thinking hopefully it will just read that one and get past. Now all I have
in the cache for this other company is the 5 record. As soon as the mail is
sent the 5 disappears and the 10 get put back in and the mail stops.

DNS server is Windows 2000
Mail Server is Sendmail on Linux
 
What is the domain name in question? Find all the NS records for this domain, then query each of the servers directly to see if they contain different entries for
the MX record. It could be that one of the servers only has a single entry for the MX record while the other server has both. Depending on which server your
windows 2000 server happens to query decides wether you get both entries or not. As a workaround, you may be able to configure a routing rule within your
SMTP server that delivers mail destined to this domain name to the correct server.

Thank you,
Mike Johnston
Microsoft Network Support
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Ace Fekay said:
In Jason <[email protected]>, posted their thoughts, then I offered my
thoughts down below: ...........

Do you have Secure Cache Against Pollution set in DNS properties (under
Advanced tab)? Since it seems to be related to a cache issue, thought to
suggest that.
Click to expand...

Yes it is on...

Jason
 
Ace Fekay said:
In Jason <[email protected]>, posted their thoughts, then I offered my
thoughts down below: ...........

Do you have Secure Cache Against Pollution set in DNS properties (under
Advanced tab)? Since it seems to be related to a cache issue, thought to
suggest that.
Click to expand...

Yes it is on...

Jason
 
Is your DNS server forwarding to anyone? Remove the forwarder and see if the problem goes away. You could also enable debug logging on the DNS
server and take a trace. Once the failure occurs, go through the traces and the logs to see where the invalid response came from.

Thank you,
Mike Johnston
Microsoft Network Support


--

This posting is provided "AS IS" with no warranties, and confers no rights. Use of included script samples are subject to the terms specified at
http://www.microsoft.com/info/cpyright.htm

Note: For the benefit of the community-at-large, all responses to this message are best directed to the newsgroup/thread from which they originated.
 
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