Question : Multiple DHCP Scopes

Is it possible to enable multiple DHCP Scopes on a NT4 SVR using DHCP Manager? If so, How? Our first and original scope works fine. However, when it runs out of addresses, the second scope will not serve addresses.

Answer : Multiple DHCP Scopes

You can run multiple scopes but they don't function like you might think. The original scope will work find, as you have discovered. However, the other scope will not give out addresses because. . . YOU HAVE TOLD YOUR DOMAIN THAT THE ORIGINAL SCOPE BELONGS TO IT.

Here are some things you may need to know.
1) You should have one DHCP server per domain per PHYSICAL subnet (separated by routers). If you have more than one on the same physical subnet from the same domain, then they should give out a range of addresses that do not overlap.
2) If you are running out of addresses, you should expand the first scope instead of trying to add another. As I said, it looks like it will work but it does not.
3) When you log onto a domain the addresses received by the computer are from the DHCP server from that domain. It is possible to run multiple DHCP servers on the same physical subnet covering two different domains just as long as the address ranges do not overlap. When you log onto the other domain, you should get an address from the DHCP server of that domain.

This doesn't always work, especially with Windows 95. The reason is that your DHCP information, including the DHCP server address, is stored in the registry. When you boot your machine it looks for the same machine regardless of the logon domain. What I have found is that it will only update if it doesn't find the original DHCP server or you manually release and renew the addresses.

Bottom line: Expand the addresses of the original scope. Addresses from additional scopes on the same machine are useless.