DNS Name Resolution problem

[mpaweb]

Hi,

I've searched high and low for the answer to this but to no avail, if anyone can help me out it'd be much appreciated!

Please bear with me on terminology, I have a fairly good understanding of DNS but when it gets down to the nitty gritty stuff I'm no expert!

A number of my customers are receiving "Message Delivery Delay" messages in return to (some of) their emails, the details say that the target mail server "cannot be contacted at this time". Sometimes the mail will eventually deliver OK (after a load of delay messages), other times it will eventually fail.

I've worked out roughly what is going on, but can't work out how to fix it!

Basically, DNS on my server appears to be resolving some names incorrectly - they are being resolved to the IP of my server itself. For example, my server is a PDC for the domain focaluk.net, and some domains are being resolved to mydomain.focaluk.net and returning my server's IP.

The server is running Win 2003 Server (SBS). If you need any more info about the setup let me know, I wasn't sure what would be pertinent.

Once again, if anyone can help me with this it'd be much appreciated - thanks in advance!!

Cheers,

Mark.

http://www.mpaweb.com

 

[ChrisAC]

An example domain with this problem would help?

Chris.

**********************
Chris A.C, CCNA, CCSA
**********************

 

[mpaweb]

Fair comment.

For example,

Name: costablancacharters.com
Address: 217.163.9.25

when I do an nslookup on that domain on my server, it returns the following:

Server: ns1.mpaweb.com
Address: 66.249.6.162

Name: costablancacharters.com.focaluk.net
Address: 66.249.6.162

 

[GlenJohnson]

Are you sure it's you? I did a tracert on costablanacharters.com and ended up with this.

13 111 ms 120 ms 170 ms ziggy.34sp.com [217.163.9.25]

Glen A. Johnson
"Trust time, for it tends to provide sweet ways out when facing bitter difficulties"
Miguel de Cervantes Saavedra (1547-1616), Spanish writer
Tek-Tips in Chicago IL

 

[mpaweb]

Are you sure it's you?

How do you mean?

The IP to which it resolves for you is the correct one for that domain. On my server it resolves to my server's IP and tacks my server's local domain on the end. This is happening for various domains....

 

[ChrisAC]

I've just queried that on your server and get;

]
[chris@uranium chris]$ dig costablancacharters.com @66.249.6.162

; <<>> DiG 9.2.1 <<>> costablancacharters.com @66.249.6.162
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 21380
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;costablancacharters.com.       IN      A

;; ANSWER SECTION:
costablancacharters.com. 86400  IN      A       217.163.9.25

So, as far as DNS goes, it looks okay but your server really shouldn't accept recursive queries from external sources (ie. from me!). You are not authoratative for this domain and so shouldn't answer my queries to your server.

As for why your server tags your domain onto the end, I have no idea. It's obviously some Windows resolution thingy m' jig!

TCP/IP > advanced > DNS > "Append these DNS suffixes (in order).

Maybe?

Chris.


**********************
Chris A.C, CCNA, CCSA
**********************

 

[mpaweb]

hmmm

Within the advanced options of TCP/IP I have "Append primary and connection specific DNS suffixes" and "Append parent suffixes of the primary DNS suffix" (!) checked (ie not a specified list as you suggest). However to be honest I haven't got a clue what those settings do so it could be related.

Not sure why my server gives you the right answer but doesn't return the correct answer "internally" - I guess that's the root of the problem!

I appreciate peoples' input so far, hopefully I'll get to the bottom of this!

 

[ChrisAC]

Have you set up any zone file containing costablancacharters.com? How are the domains that do not resolve correctly related to you?

Chris.

**********************
Chris A.C, CCNA, CCSA
**********************

 

[mpaweb]

costablancacharters.com is nothing to do with me, i'm not hosting it. Its just one of the various domains which, when one of my customers send an email to it, suffer from this "message delivery delay" problem (caused (i think!) by the DNS issue I'm trying to resolve here)!

 

[ChrisAC]

Have you had a look through your email logs on the server to see if MX resolution is failing for mail for external domains?

Chris.

**********************
Chris A.C, CCNA, CCSA
**********************

 

[mpaweb]

its not failing for 90%+ of domains, the logs just say that the domain(s) in question "cannot be contacted", as per the DNS problem...