Win2000 DHCP not working after conversion

[jpyoungats]

I recently converted a Windows 2000 server running DHCP. Afterward, it stopped passing out IP addresses.

I exported the DHCP database and imported it on to another Win2000 VM and it wouldn't pass out any IPs either.

I then imported the scope into a physical machine and it worked fine.

All of these servers (and the scope) are on the same subnet, no vlans, no routers, etc.

DHCP is authorized and the scope is activated and there are plenty of addresses left in the scope.

Is there something in the vNICs or vSwitches that might be blocking broadcasts to the VMs?

Thanks,

Joel

[RParker]

Not a VM issue, this is a Switch / Windows issue.

You have to configure the switch to allow the IP for this machine for the DHCP helper address. Contact your Network admin to complete this, then it will work.

[jpyoungats]

I've put ip dhcp-helpers on routers, not switches...

But there's no routing in my situation.

Joel

[RParker]

Well routing is one thing, it's the ability of the switches to allow DHCP zones, so you can't spoof IP addresses. If you didn't do it, I don't see how you expect the DHCP to answer on the zone without the use of helper addresses, since that's what they are for.

If you turn the other DHCP server off, and bring up a machine. Release / Renew IP. What happens? It should get a time out, no DHCP available to service the request. If it gives you an IP, there is the culprit. Another DHCP is giving out an IP.

Either way it's a configuration problem with your Windows machine, not VM. The vSwitches don't block anything in or out by default. The only firewall is for the console on the ESX host itself (traffic directed at the ESX server). Other than that, it does no filter / NAT / Firewall.

Or make the IP static on the VM, and make it the same as the Physical server, that will verify what the problem is.

[TomHowarth]

Check your VM for hidden devices, in Device manager, I think you may have a suprious NIC. I have DHCP servers virtualised with out the use of DHCP helpers, the are only utilised on Routers to allow cross sub-net zones or to issue out IP addresss to none local subnets.

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Tom Howarth VCP / vExpert

VMware Communities User Moderator

Blog: www.planetvm.net

Contributing author for the upcoming book "VMware Virtual Infrastructure Security: Securing ESX and the Virtual Environment”.