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DHCP not giving out leases to clients

Hi

I have a Windows 2003 Standard server and have installed and configured DHCP and created a scope. The server is authorised, and is all ready to serve my clients.

However, no clients on my network can obtain an IP address via DHCP, but there are no errors in Event log.

If the clients are assigned a static IP on the same subnet as the server, they can connect to and ping the server without problem.

I have two NIC's in this server, but disabled the second NIC (which is the management NIC used for Network Load Balancing) in Properties > Advanced > Bindings.

Any tips much appreciated.



Gareth
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localgareth
Asked:
localgareth
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3 Solutions
 
Nirmal SharmaSolution ArchitectCommented:
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mftealCommented:
I would start by stopping and restarting the dhcp service on the server. Also, check the event logs for anything helpful.

Assuming you have stopped and successfully restarted the dhcp server service and see no errors in any system logs, I would say to remove the service, reboot, and reinstall the service.
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localgarethAuthor Commented:
SystmProg: I had already set binding on just one card.

mfteal: Tried stopping, starting, rebooting, unauthorising, removing the service and reinstalling - but still no leases are issued.

The annoying thing is, there are no errors in event log. When I restart the service, I get a message in event log saying everything is fine and clients are ready to be served addresses.

Is there any advanced logging I can use? Could this be related to Network Load Balancing?


Thanks


Gareth
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mftealCommented:
Found a newsgroup posting that may be relevant:

Since the DHCP client will use a broadcast packet DHCPDISCOVER to find the
DHCP server, it will be no use if two interfaces (routers) for the DHCP
server are in the same subnet. Even, if may cause a problem as listed in
the following articles:

265129 Multihomed DHCP Server Do Not Allocate IP Addresses
http://support.microsoft.com/?id=265129

310844 Multihomed DHCP Server Assigns Duplicate IP Addresses
http://support.microsoft.com/?id=310844

Therefore, please re-consider your plan for a NLB of the DHCP services,
since normally we do not use this unless the clients are separated to
different subnets.

I hope this helps. Have a nice day.

Reference
=======
Q169289 DHCP (Dynamic Host Configuration Protocol) Basics
http://support.microsoft.com/default.aspx?scid=kb;EN-US;Q169289

Q120932 DHCP: Spanning Multiple Subnets
http://support.microsoft.com/default.aspx?scid=kb;EN-US;Q120932

Q161571 Using DHCP "Superscopes" to Serve Multiple Logical Subnets
http://support.microsoft.com/support/kb/articles/q161/5/71.asp
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localgarethAuthor Commented:
mfteal - excellent links :-) but I think my setup is already identical to how the document describes.

I have two servers, and am (sucessfuly) using NLB for Terminal Services.

My server NICs in the Server where I plan to run DHCP are..

NIC1 (LAN Connetion)
IP: 10.255.255.1
SUBNET: 255.255.255.0
GATEWAY: 10.255.255.254
VIRTUAL IP for NLB 10.255.255.3
Network Load Balancing is bound to this adapter

NIC2 (Management Interface)
IP: 172.16.0.1
SUBNET: 255.255.255.0

NIC2 in Server 1 is connected to NIC2 in Server 2 bycrossover cable, so it is physically seperate from NIC1.

Any thoughts?

Thanks



Gareth

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mftealCommented:
Do you see any active leases? I'm just wondering if the DHCP server has issued (or thinks it has issued) any addresses at all?

One other thing to check is the below article. You may not have used Dhcpexim.exe, but wouldn't hurt to check the relevant registry key:
http://support.microsoft.com/default.aspx?scid=kb;en-us;287031
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mftealCommented:
Oh, any chance it is a router issue? If there is a router between your clients and the server, would it be possible to try connecting a client PC to the same switch that the server is on temporarily to make sure the router isn't blocking dhcp packets?
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localgarethAuthor Commented:
There are no active leases - the DHCP server is just sitting and waiting, and doesn't seem to respond to any client requests for leases.

There is no router between the server and clients, just a unmanaged switch.

Just looking at KB 287031 but not sure it will help, it also doesn't seem to be for Server 2003, but I may try this anyway.

Thanks



Gareth
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mftealCommented:
Any chance you've accidentally installed a DHCP relay agent on the server as well as having it as a dhcp server?

Just check Routing and Remote Access, under the server name, IP Routing, you shouldn't see it enabled. If you either have it configured on the DHCP server to route to itself or have it on another server to route somewhere else this would prevent your DHCP server from being asked for addresses.
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Netman66Commented:
Do you have DHCP setup on each server?  With half the scope on each server?

Using NLB introduces a new set of challenges while trying to run a network service.  Since it will "round-robin" from server to server, then each server will require DHCP running.  Since you cannot duplicate scopes, you'll need to give half your addresses out from each server.

You'll also have to have DHCP listening on the virtual IP, not the NIC's real IP.

Advise.
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ckratschCommented:
On a site I worked on yesterday:

They have a little SonicWall with 10 internet CALs.  The SonicWall would scavenge the network for IP devices and assign CALs to anything it finds - including four printers and a wireless access point.  Considering that they have 9 computers on the network, that would run over the top of the CAL limit.

Now, the SBS2003 machine was running DHCP, not the SonicWall - but when the SonicWall ran over CALs, it would prevent computers from receiving DHCP anyway, some computers were not able to connect to the server, weird stuff like that - all on the LAN, not on the WAN.

The solution there was to enter Deny Access rules in the SonicWall for the printers and WAP, then restart the SonicWall to clear the license count and have it reassign CALs to clients on the LAN.

Probably not related to this, but I just had to mention it.
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localgarethAuthor Commented:
mfteal, thanks for the idea - but I'm not using any DHCP relays.

netman66, I dio have half my overall DHCP scope on each server, so there is no overlap. Anyway, NLB is only used for TCP port 3389 for terminal services.

I have a feeling this is something to do with Network Load Balancing, 'cos if I resetup NLB on the servers using just one NIC and disabling the other, it seems to work fine. For now, this will be my workaround until I have time to do more testing.

Thanks to all for helping :-) I'll split the points 'cos some good suggestions were made.

Thanks



Gareth
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Nirmal SharmaSolution ArchitectCommented:
Thanks!
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