DHCP Gateway Missing

[nevets2001uk]

We've had DHCP setup for a while now and until recently things seemed to be OK. Now however we are getting a number of clients who are getting addresses but no Gateway (even though this is specified in the scope options and works for others).

At first we noticed it on 1 client who we ended up making fixed IP. However now it seems more widespread.

If we login as Admin and renew the gateway reappears and works fine.

Any thoughts as this is now becomming it big problem for our users.

Steve G (MCSE / MCSA:Messaging)

 

[chipk]

Just a shot in the dark here, but do you have a Cisco network? Does this only happen when you first boot up a PC? If yes to both of those, try setting your access ports to "spanning-tree portfast". There may be a delay in coming up on the network that is causing partial DHCP info to be lost.

 

[TweakMYbox]

Is this isolated to a particular subnet?

Mike Fegan

http://www.TweakMyBox.com

Great resource for free tools, and tech chat. Check out the Babe of the Week!

 

[nevets2001uk]

Sorry for the delay in replying. I've been away from the office for a bit and forgot about this post!

We are a single subnet site and use the router to connect to the company WAN for Internet access via a proxy. We do use Cisco gear but I'm afraid it was configured for us and as such I'm not sure how to check how it's setup.

However this problem is only affect perhaps 10 out of 100 users. Many share the same switches and backbone to our servers.

Users seem to get a valid DHCP address however the gateway is simply not provided. If we login as Admin and renew it appears straight away. After a reboot the users often report that the gateway is missing again.

One error we are recieving in a client's event log is...

SOURCE: DHCP
EVENT ID: 1003
Your computer was not able to renew its address from the network (from the DHCP Server) for the Network Card with network address 000D56CE4335. The following error occurred:
The operation was canceled by the user. . Your computer will continue to try and obtain an address on its own from the network address (DHCP) server.

Followed by...

SOURCE: DHCP
EVENT ID: 1007
Your computer has automatically configured the IP address for the Network Card with network address 000D56CE4335. The IP address being used is 169.254.124.116.

However they get full network access and when we ipconfig /all they have a valid network IP (ie. not the autoconfigured one it claims to have used!).

Any thoughts are much appreciated as this is very annoying for our users.

Steve G (MCSE / MCSA:Messaging)

 

[ashpp]

With these errors I would suspect a switch issue such as

http://support.microsoft.com/kb/q168455/

Another possible issue is a rogue DHCP server on the network. Packet sniffing would be helpful.

 

[nevets2001uk]

Thanks for all the help with this issue. We have now enabled portfast for the problem clients and this seems to be solving the problem. Once we are happy with this test we will roll this out to all client ports.

It seems odd that this was only affecting certain users across a number of switches but not the other users.

Steve G (MCSE / MCSA:Messaging)