DHCP Issue

C

compaqman

Member
UPDATE: Issue resolved.

I performed a System Restore to April 14, which consisted of a Windows Critical Update.

Everything seems to be functioning correctly now.

Thanks to beers for his gracious assistance!

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Hello all,

I have a Windows 7 system that recently, DHCP has stopped working.
By not working, I mean nothing happens during ipconfig /renew. It just hangs there

This is my work machine, and I am the Administrator for it, and 9 other PCs, which have no issue obtaining an address from DHCP.

I first noticed DHCP issues when I tried connecting to the phone network through my second NIC. Somehow it had released the IP, and renewing it didn’t work, so specifying a manual address resolved the issue.

As I was diagnosing the issue, I released the IP on the computer network NIC, and was unable to obtain an address thereafter. Again, specifying a manual address works.

So the main reason I’m trying to figure this out, is to prevent other issues that may arise due to this seemingly small issue.
I’ve done the following diagnostics:
  • Reset the TCP/IP stack manually
  • Reset the TCP/IP stack with Microsoft’s “Fix It”
  • Restarted the DHCP service
  • Rebooted the machine
  • Used a packet analyzer
  • Rouge DHCP detection software (which in fact, did detect the authorized DHCP on the phone and computer network)

Although applying a static address works, I would like to get this problem fixed.


System Info:
  • Windows 7 Pro, 64-bit
  • Realtek NIC connected to the VoIP network
  • Intel NIC connected to the Computer Network


Thank You,
- Jon
 
Last edited:
What kind of DHCP server are you all using (Windows/dhcpd)?
How long are your lease times?
Can you ping the DHCP server IP?

Sometimes you'll get this sort of behavior with really long leases and then losing connection to the DHCP server. Also I've seen instances where someone fat fingers the IP Relay address in the switch/SVI. Do you all have an elaborate topology?

What did your packet analyzer state? Did you see any DHCPDISCOVER broadcast frames originating from your PC? Were there any DHCPOFFER frames received from anywhere?
 
We are using Windows Server 2008 R2, it is our Domain Controller, and File Server.
Lease times are 30 days, but I have removed all instances of my machine from the “address leases”
Yes, I can ping the DHCP server IP.

On the Computer Network, there is a managed Switch between my workstation and the server. Nothing special there.

On the Phone network, we have a hosted PBX over fiber optics, to a switch in our office which connects the VoIP phones.

I was able to get DHCPDISCOVER and DHCPOFFER from the proper DHCP servers when I used the “Rogue DHCP Detection Software”

No DHCP protocol activity whatsoever with windows IPCONFIG

And, it is only my PC that is experiencing any issues with DHCP. All other machines are totally fine and can renew / release their addresses without any trouble.
 
Glad you were able to get it working. I hate higher level application/OS issues that affect other lower layer services :P

Do you recall which patch ID it was, out of curiosity?
 
I totally agree with you about the upper layer services, they are awful to troubleshoot, as I have just experienced.

As the admin, I should have paid more attention to which update/hotfix/patch it was that could have broken DHCP operation.

In addition to the windows update, there were was a handful of 3rd party application updates.

I'm going to update my system during the week, and reboot after every update, to ensure that everything is working the way it is supposed to. Typically we keep our machines on 24/7 unless there are pending updates and such.
 
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