MX Records for external domains not resolving properly

  • Thread starter Thread starter Steve Mart
  • Start date Start date
S

Steve Mart

I have recently installed 2 new Windows 2003 DC's running as DNS servers.
These servers seem to function fine with the exception of how they handle MX
records of external domains. I can resolve A record lookups fine, but when
I try to locate the MX records in the same external domains I get DNS
request timed out messages.

For example if I do the following commands:
Nslookup
mx1.earthlink.net
Click to expand...

I receive the following:

Server: dc03.ri.org
Address: 10.100.169.209

Name: mx1.earthlink.net
Address: 209.86.93.226

If I try to locate the MX records for the Earthlink domain by trying the
following:
set q=mx
earthlink.net
Click to expand...

I receive DNS request timeout messages on my Windows 2003 servers.

My 2 other Windows 2000 DNS servers have no problems resolving the query
properly. Any suggestions would be appreciated.

Thanks.

Steve
 
Steve said:
I have recently installed 2 new Windows 2003 DC's running as DNS
servers. These servers seem to function fine with the exception of
how they handle MX records of external domains. I can resolve A
record lookups fine, but when I try to locate the MX records in the
same external domains I get DNS request timed out messages.

For example if I do the following commands:


I receive the following:

Server: dc03.ri.org
Address: 10.100.169.209

Name: mx1.earthlink.net
Address: 209.86.93.226

If I try to locate the MX records for the Earthlink domain by trying
the following:


I receive DNS request timeout messages on my Windows 2003 servers.

My 2 other Windows 2000 DNS servers have no problems resolving the
query properly. Any suggestions would be appreciated.

Thanks.

Steve
Click to expand...

You'll either want to disable the new EDNS0 feature or update your firewall
to support the new industry feature.

832223 - Some DNS Name Queries Are Unsuccessful After You Upgrade Your DNS
Server to Windows Server 2003:
http://support.microsoft.com/?id=832223


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Ace

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Ace Fekay, MCSE 2003 & 2000, MCSA 2003 & 2000, MCSE+I, MCT, MVP
Microsoft Windows MVP - Windows Server - Directory Services

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Thank you. The problem was resolved by
Well, the above fixed the UDP "oversized" packets
(EDNS0) issue; but since you're at it I'd also check
if your firewall is allowing DNS traffic over TCP, to do
so, just try the following

nslookup
server 4.2.2.2
set vc
set type=mx
earthlink.net

the second line tells to nslookup to use an external
server, the third to use TCP queries in place of UDP
ones, if the firewall isn't blocking TCP DNS traffic then
the last line (the query) should get an answer otherwise
you'll need to setup your firewall to allow DNS query
traffic to flow toward external servers (to 53/TCP)

Regards

--

* ObiWan

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