Router as DHCP....!

gauravshar · ‎03-08-2008

All,

Even if my LAN is 10.15.200.0/23, can i use just 10.15.200.0/24 for DHCP dynamic assigned range.... and leave rest of the IP's (neither excluded range nor dhcp rang)

ip dhcp pool XYZ

network 10.15.200.0 255.255.255.0 <=> i want to use this range rather than 10.15.200.0/23 (complete LAN IP range). Can i use it?

I just want my one dhcp server to cater first 254 IP's for one floor and second pool of 254 IP's should be cater by dhcp server which is hsrp peer of the previous router.

--gaurav

Jon Marshall · ‎03-08-2008

Hi Gaurav

You could do this but any device that receives an IP from DHCP will have a subnet mask of 255.255.255.0. If you have any non-DHCP devices with the subnet mask 255.255.254.0 then they will think the DHCP machines are in the same subnet but the DHCP mahines will think that the non-DHCP servers are in a different subnet.

Jon

gauravshar · ‎03-08-2008

Hello Jon,

just want my one dhcp server to cater first 254 IP's for one floor and second group of 254 IP's should be cater by other dhcp server which is hsrp peer of the previous router.

Suggest something to help me acheive the best design..

--gaurav

Richard Burts · ‎03-08-2008

gaurav

You certainly can put the first 254 addresses into one DHCP server (or router acting as DHCP server) and put the second 254 addresses into the other DHCP server. But it probably will not work as you want it to. You describe it as being one set of addresses for one floot and the second set of addresses for a second floor. But if the routers are HSRP peers then both servers are in the same broadcast domain. This means that both servers will hear any broadcast DHCP request. And both servers will respond to the DHCP request. It is highly unlikely that addresses on one floor will be assigned only by the server that you intend.

And as Jon points out the DHCP clients will get a subnet mask of /24. This will introduce some complication as stations in the first half of the real range attempt to communicate with stations in the last half of the range.

HTH

Rick

HTH

Rick