DHCP

[andycrane]

If I have FOUR Scopes (for four different subnets) set in DHCP manager, How do the clients pick up the right address for the correct subnet?

[POBrien]

I read through Supporting Windows NT in the Server Enterprise pages 169 thru 178. Specifically on page 174 It describes your circumstances and states that you should setup a dhcp server on each subnet and connect the subnets via routers that can act as (BootP) rfc 1542 relay agents. If I recall, you don't have to use routers specifically coded with BootP. You can use 1 pc on each subnet to act as a dhcp relay agent. This would be a total of 8 pc's altogether.

1 subnet = 1 dchp server and 1 dhcp relay agent.

4 subnets = 8 pc's

[gary0907]

This is correct, if you have multiple scopes active on a DHCP server, on a single network segment there is no real way to restrict which clients receive from which scope. In windows 2000 this can be done by setting device types at the client, which DHCP reads and allocates from the appropriate pool for that device. With regard to the DHCP forwarding agent, this is a fairly good idea with windows NT as any client can intercept DHCP requests and pass them through a router to the DHCP server. With windows 2000 it is different in the fact that only a server can be configured as a DHCP forwarding agent. Alternatively, most routers support BootP, but again be aware that unless you carefully control the ports allowed to pass broadcasts, you will have problems with excessive additional broadcast traffic.

[webjunkiemcse]

When creating a DHCP scopes, you can set up specific address ranges for a given subnet.
The example I am including uses 2 address ranges (10.0.0.0 and 10.0.1.0) and 2 subnets (net A and net B) purely for simplicity in explanation.
If you want half of Net A in the 10.0.0.0 subnet and half in the 10.0.1.0 subnet you can exclude half the addresses from the scope used on subnet A and then exclude the remaining 10.0.0.0 addresses from the scope in use on subnet B.

This will use only address included in the scope for Subnet A to be used by computers on that subnet and the left over addresses will be used by computers in Subnet B.


Derek Schauland
MCSE on Windows 2000