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Redundant DHCP for NT/2000

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by yisrael 1 view

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I am looking for a good tool to help me provide redundancy for a NT 4.0 DHCP server. The NT 4.0 DHCP Service does not allow for 2 DHCP servers with the same scope to allow for a fail over. Does anyone know a way to solve this problem? The only option I heard about was to have 2 servers with half the scope each. This requires at least some screaming in the office (not recommended).
P.S. I don't know much of windows 2000. If Windows 2000 addresses this problem, I am all ears.

5 replies

by zbrain75

I wouldn't exactly say there is no failover. Although not very convenient, you can set up two DCHP servers in your organization. It does not allow a very efficient use of IP addresses when you have two or more DCHP servers which can fill in for another in the event of failure, but it is easily done.

Lets say you use a class C network and have 100 machines on the network. You have up to 254 assignable addressses. You set up two dhcp servers, one with address scope 1-128 and the other 129-254. Obviously if you have more than 128 machines, you MAY (maybe) have a problem or may need more IP addresses. However, in this case, the two DHCP servers can cover for each other if the other one fails.

The only real problem beyond that is that the user's IP address may change if they reboot. So long as they keep their computer on and their lease does not come close to its expiration time, the IP address does not change. In the case of IP addresses changing, you can deal with dynamic changes to IP addresses by using WINS.

What problems would cause the screaming?

by yisrael

What happens if the DHCP server for half of your class c network (lets call that DHCP server A) croaks during the night shift in a production facility? Do you want to have to manually setup the other one (DHCP Server B)to cover for his dead friend at 2 in the morning?

by skkzarg_death

that, provided your client # is small enough, Server B will be able to provide enough addresses until you come in during the morning.

Skkzarg

by yisrael

Who wants to wake up at 2 in the morning with screaming users just so you can manually configure something that has the ability to be automated?

by kelster

This doesn't save you the 2 am phone call but it may save the drive in to work. Install the DHCP server to a second server, set up the scope, and then deactivate it. If you do get the dreaded call log in remotely and use the Network Based Client Tools to access and activate your backup DHCP Server.

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