Hi,

We have a Dell PC server here in our office with Windows Server 2003. Everything was working fine until about aweek ago, it started to go wrong.

There are about 30 computers/users hooked on this network. I had to get the IP addresses based on machine names, and assign it manually in each computer, as none of the NIC obtained IP automatically.

I was advised by our IT manager who's based in another country to install the security update for Win Server 2003. It did not help as well.

I'm sure there are experts out there who can help me with this.

Please accept my appreciation in advance for your help

kalidas

So let me know if my understanding is correct:

- 30 Machines all worked fine and obtained their IP addresses automatically
- About 1 week ago they ALL stopped getting IP addresses automatically
- So you setup IP addresses on them manually

If that's the case then this points to the DHCP server as the source of the problem and it is highly unlikely that all 30 machines would break at the same time.

If on the other hand your Windows 2003 server IS your DHCP server and all 30 machines dependent on it stopped getting IP's then chances are the DHCP setup went astray somewhere on that server. If this is the case then I'd look at the following:

- Check to make sure the DHCP Service is running
- Check to see if there are any error messages for the DHCP server in the event logs
- Check to make sure that your DHCP server is not running any kind of firewall on it that is preventing DHCP requests (disable if you can to troubleshoot).

Casey

Hi

Thanks for the solution

Yes, we have already indentified the source of this problem. You are right about the DHCP server.

When I was joining a new notebook to the company domain, I set it to obtain IP automatically, and it didn't work. I did an ipconfig, it showed different IP. And then I tried to enter the IP based on the machine name registered in the DHCP server. It worked.

When I asked for advice from the IT person in another country, he said that someone intentionally or unintentionally has opened a DHCP server and all your client PCs are obtaining IP from there instead of from our company DHCP server. He was asking me to find out which machine is running DHCP.

I have no idea on how to do this as I don't have such good knowledge in networking to find that out.

The server is connected to a Cisco router. And I'm not sure whether this is unusual, but I was also questioned about this. In the DHCP - server - Scope - address leases - I see machine names which are not ours

For an example - our machine name with domain starts with
SAMM001.ad1.nos.net

According to our IT policy, we are not allowed to give any names for new machines. But there are names which I have never created before. Is it even possible for someone else to access the server and create it

Thanks in advance

Kalidas

Sometimes people bring in their own wireless routers into the office and plug it in the network without really knowing the consequences... one of which is that when they plug the LAN side it becomes a DHCP server on your network. So I would say look for a wireless router somewhere as a potential source of the DHCP problem.

Do you have access to your Cisco router? If you do then that can also be used to track down the DHCP server.

I just wanted to add to Casey's excellent diagnosis. You NEED to send an e-mail to all employees asking whoever connected the router to come forward. Include in the e-mail that there will be no disciplinary actions for this, but this action had serious repercussions on the network. The company needs to know why this was done so it can provide resources in the future for the functionality. This will also help you confirm that this is what happened.

You then need to publish an acceptable use document that specifies what can and can't be done on the company network.

I am also curious as to why your IT support suggested installing the Security patch (though you should be keeping the server up to date on all patches). My initial reaction from reading your first post was the same as Casey's, something went wrong with your DHCP server. So the advice should have been the same as Casey's, find where your DHCP server is operating from and find out what went wrong with it.