Losing DNS Settings

[kcdanielj]

Hello,

I am having an issue that I've never seen before and so far have been unable to resolve. we have one particular PC which periodically loses it's DNS settings . What I mean by this is at some point, we will find it cannot do DNS lookups. Doing a NSLookup, I find that it is then trying to query itself (127.0.0.1) rather than the DNS servers. Doing an ipconfig /all I find that there are no longer any DNS servers listed in the output. The PC is getting it's settings from DHCP. The only way to resolve is to reboot the PC. Here is a list of things I have tried with no luck.
[ul]
[li]Unplugging and replugging in the Ethernet cord does not fix the issue.[/li]
[li]ipconfig /release, ipconfig /renew does not fix the issue.[/li]
[li]Using the network troubleshooter does not find nor resolve the problem.[/li]
[li]I have updated the driver to the latest level with no change.[/li]
[li]I have stopped the PC from going to sleep or hibernating.[/li]
[li]I have statically assigned the DNS server IP's with no change.[/li]
[/ul]

It just happened again just now and I went into the driver and turned off the Energy Efficiency option. I am not hopeful that it will resolve the issue though because I have the same laptop and have never had to adjust those settings.

Any other ideas would be greatly appreciated.

Daniel

 

[edfair]

Have run across this using 7 with intermittent failure to get information from the DHCP server. Mine was failure to get IP address and started to fail within 2 weeks of XP machines being replaced by 7 and eventually failed 5 for 5. Put an XP back for test and everything worked. It also continued to fail across a router replacement.

Ed Fair
Give the wrong symptoms, get the wrong solutions.

 

[kcdanielj]

Hello Ed,

Thank you for your reply but in my case the system is not failing to get it's IP or DNS addresses. Everything works great for part of the day but then suddenly DNS queries start to fail and at that point ipconfig shows no DNS servers listed. Even if it is statically set and I confirm that the DNS IP's are there in the NIC IP 4 settings. Running an ipconfg shows no DNS servers at that point.

 

[cdogg]

1. Is this in an office environment where other PCs/laptops using the same settings are not having issues?

2. If so, do you connect over Ethernet directly to the wall plate, which in turns goes directly to a network closet switch? Or is it going through a hub/switch/router on its way to the network closet switch?

3. Are you able to test another PC/laptop on the same Ethernet connection to see if it has the same issue?



-Carl
"The glass is neither half-full nor half-empty: it's twice as big as it needs to be."

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[kcdanielj]

It is an office. I have the identical laptop in my office with no issue. We both connect to a wall plate which is wired back to the the server room. We are both connected to the same large 48 port switch that our servers are connected to. We do both use docking stations. I will try connecting him directly to the Ethernet port rather then through the docking station. This is a very strange one. IP's for the laptop, subnet and gateway never go anywhere. In fact IP based connections continue to work the whole time. It's just DNS IPs disappear.

 

[cdogg]

Definitely strange. See if ipconfig /flushdns brings DNS back without rebooting. Also check that the DNS Client service is still running when things go south.

Also, is the software configuration identical on both laptops? Check "Programs and Features" to be sure. Wondering if a 3rd-party software antivirus/firewall is to blame. It could also be some kind of malware infection. Doesn't sound like an issue on the network/server side at this point, since other workstations aren't having the issue.

And finally, check to see if the user is connecting to a VPN throughout the day. Some VPN configurations can cause the local DNS cache to suddenly fail when the session is disconnected.

 

[goombawaho]

The best test (as stated by cdogg) is to put another PC in that location (same network jack and cable) just to see if it's a physical issue with the network cable, jack, wiring in the wall or patch panel/switch port in the back room. Crazy things can happen between the ethernet jack on a PC and the switch port it's plugged into in the back room.

"Living tomorrow is everyone's sorrow.
Modern man's daydreams have turned into nightmares.

 

[Sympology]

The fact it gets applied later in the day could suggest it to be a GPO.

Check out the machines settings after it happens:

https://technet.microsoft.com/en-us/library/dd197486(v=ws.10).aspx

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We've all heard that a million monkeys banging on a million typewriters will eventually reproduce the entire works of Shakespeare. Now, thanks to the Internet, we know this is not true.

http://alvechurchlounge.org.uk

 

[cdogg]

Sympology,
It's an idea and worth checking, but I would imaging other workstations would be having the same issue if it was a GPO.