DHCP and multiple VLANS



We currently have a large network (2000+) devices running in a single vlan
with one DHCP server. We are going to be breaking down the vlan by floors(9)
to smaller vlans. We would like to use only one DHCP server. How do I setup
DHCP to recognize the proper scope to assign an IP from based on the floor
that the computer connects too?

Steve Duff [MVP]

You need to enable a DHCP relay agent IP in each segment so that DHCP messages can get to and from your server. This depends on the
switch/router setup you are using. (With Cisco switches it is the "ip helper-address.." configuration statement.)

On your server you then just define a scope for each VLANs IP subnet. The server will match the right scope to the relay agent
source gateway IP - which the router adds when it forwards the DHCP broadcast to the server.

Of course be sure to adjust the default gateway in the scope options as appropriate for each VLAN.

This has a more technical information (watch the wrap):


Steve Duff, MCSE, MVP
Ergodic Systems, Inc.

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