Cisco DHCP server feature questions

[IllegalOperation]

Hello all, this was originally in the Cisco routers forum....but perhaps it can be answered in here.


I understand you can create multiple address pools on a Cisco router. My question is, how do clients know which pool to grab an address from? Lets say if I have two Cisco edge routers (A and B) connected to my Cisco core router which is running DHCP services. I create two pools, one for each Cisco router. Address pool A is for the clients connected to router A, and pool B is for the clients on router B. How do the clients from router A obtain an address from pool A? DHCP is configured in global mode, so I cant stick an address pool on each physical interface. Somehow Im missing a command to make this happen, but I dont see any in the literature I am reading. Thanks for the help...

 

[CCNEH]

Heres an example:

In the dhcp config you assign a network

ip dhcp pool test1
network 192.168.10.0 255.255.255.0
dns-server 192.168.30.10
default-router 192.168.10.8
netbios-name-server 192.168.30.28
domain-name world_nt

As you can see the subnetwork in this case is 192.168.10.0
so the IP addresses for the 10.0 range would be handed out on any requests made to the 10.0 interface on the subnet.

Hope this helps,
steven

 

[isokocons]

Lets assume this is your config:
Core Router A:
Scope 1: 192.168.10.0/24
Scope 2: 192.168.20.0/24

Branch Router 1: If you want clients connected to this router to get dhcp ips from scope 1 above, then the router LAN interfacing facing these clients must be assigned an ip address in the 10.0 range.

Branch Router 2: Will have its LAN interface address in the 20.0, for clients in its interface to get ip address from scope 2.

Remember to configure ip helper address on both routers. When the ip helper forward the dhcp request to the core router, it also will forward the ip address of the interface facing the client, this will make the dhcp server to assign the appropriate ip.

hope this helps.

 

[Whoheard]

To answer your question, the router, A or B, forwarding the DHCP request to the core router is going to change the end user broadcast into a uni-cast destined for the core router. The core router reads the network ID from the frame and determines what network scope should be used. Sound Good?

bob

I know what I know and that's all I know. What I don't know I'll find out.

 

[IllegalOperation]

Thanks guys. Greatly appreciated....