Solved

DNS NSLOOKUP problem

Posted on 2013-06-11
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Last Modified: 2013-06-11
I had problem emailing to one client, now I narrowed down to it's DNS problem, it looks like internal DNS problem, but weird thing is the problem seems to be mixed with their problem as well.

First, I can nslookup to their mail server 'service101-us.mimecast.com' at my DNS server and gateway. Then when I nslookup to the mail server from any workstations/servers other than my DNS server, it times out. So, I thought it was our DNS server problem or firewall or any blocking dns request to the DNS server, I rebooted, restarted the DNS service, it's still the problem. I disabled Antivirus on the server, disabled firewall, doesn't help. DNS server can nslookup it, but workstations and servers other than the DNS can't.

This problem happens only for the specific address 'service101-us.mimecast.com'. That's why I'm confused.

Below is the nslookup command I ran to troubleshoot from workstation, my DNS server, and their DNS server.

==========================================
Nslookup at my DNS server:
C:\Documents and Settings\user1>nslookup
Default Server:  FS2.mydomain.local
Address:  192.168.xxx.xxx

> service101-us.mimecast.com
Server:  FS2.mydomain.local
Address:  192.168.xxx.xxx

Name:    service101-us.mimecast.com
Address:  207.211.31.80

>








==========================================
Nslookup at my workstation, all other PCs and servers return the same:

C:\Users\user1>nslookup
Default Server:  FS2.mydomain.local
Address:  192.168.xxx.xxx

> service101-us.mimecast.com
Server:  FS2.mydomain.local
Address:  192.168.xxx.xxx

DNS request timed out.
    timeout was 2 seconds.
DNS request timed out.
    timeout was 2 seconds.
*** Request to FS2.mydomain.local timed-out
>



===================================================
Nslookup to the client's mail server' DNS server:

C:\Users\user1>nslookup - dns01.mimecast.com
Default Server:  UnKnown
Address:  193.118.78.141

> service101-us.mimecast.com
Server:  UnKnown
Address:  193.118.78.141

Name:    service101-us.mimecast.com
Address:  207.211.31.80

> service101-us.mimecast.com
Server:  UnKnown
Address:  193.118.78.141

Name:    service101-us.mimecast.com
Address:  207.211.31.80

>
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Question by:crcsupport
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by:MARTiN
MARTiN earned 100 total points
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run "ipconfig /flushdns" and try again.
Also check nothing weird has managed to get into your "hosts" file.
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by:Thomas Grassi
Thomas Grassi earned 400 total points
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How about ipconfig /all from your computer post results

Are your computers using dhcp or static ip addressing?

Can you telnet to the exchange server using port 25 via ip address ?
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by:crcsupport
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I did ipconfig /flushdns already, didn't help
I tested on both machines with dhcp, static, didn't help
telnet to the mail server with hostname fails, expected since DNS problem
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LVL 23

Assisted Solution

by:Thomas Grassi
Thomas Grassi earned 400 total points
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Where is your DNS server? what OS server is it running on.

Look at the DNS server logs.

Sounds like the dns server is having a problem.
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LVL 1

Author Comment

by:crcsupport
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Windows 2003 SP2, it's running in LAN.
has static IP, no NAT IP configured.
has domain name FS2.mydomain.local.

I didn't have any problem running the DNS server without NAT IP (public IP) and non external DNS hostname so far. But will it be a problem?
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LVL 23

Assisted Solution

by:Thomas Grassi
Thomas Grassi earned 400 total points
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Do you see the domain computers listed in the forward lookup zones you should see your domain name and under that all registered computers should be listed.

also reverse lookup zones they should be listed
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Author Comment

by:crcsupport
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Yes, I checked forward, reverse zone, all working.

I have backup DNS server, I nslookup the trouble external DNS hostname, it resolves without problem. Now I really think it's problem of the primary DNS. I already restarted by right-clicking on DNS server in mmc, but seems like I have to do it again.
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Accepted Solution

by:
Thomas Grassi earned 400 total points
Comment Utility
On your windows 2003 DC you should have DNS event logs
Even in the MMC with DNS added it has DNS Events

You have to have many errors listed.

If not the go to the properties on the DNS server and check event logging settings
change to log all.
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Author Comment

by:crcsupport
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All events were selected in event logging, nothing shows.
I just restarted DNS, it works.
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