Two DHCP servers

[Schroeder]

I have a relatively simple network involving two subnets. I've had a DHCP server running on my main subnet for a while. Yesterday, I installed a DHCP server on the other subnet where, up 'til now the machines have been using static addresses.
Is this the wrong solution for giving machines on the second subnet dynamic addresses? The problem is, when a machine on either subnet requests an address, either DHCP server may answer it. Sometimes a machine on one subnet gets its address from the server on the other subnet.
How can I keep the two DHCP servers from talking to machines on the wrong subnets?

 

[Bealy]

That shouldn't happen.
When the PCs start up they broadcast for a DHCP server on their subnet. You could have a DHCP server on every subnet if you want.

 

[Schroeder]

Is there a setting on the client machines that I'm missing? How do they know what subnet they're on until they get an address from the DHCP server?

 

[Bealy]

You need to make sure the subnets are seperated by a router. This will stop broadcasts past a subnet.
The clients need no configuration.

 

[Schroeder]

I guess that's my problem. The two subnets are at different locations connected by a leased line. There are Cisco concentrators at either end, not routers. I would imagine I could tell those concentrators to drop DHCP packets. That would fix it, right?