2nd Ip helper address

jjames · ‎09-27-2007

Is is possible to set up a second ip helper address on cisco routers as a backup should the primary dhcp server be down?

paolo bevilacqua · ‎09-27-2007

Yes. B'casted packets will be duplicated and routed to all helper addresses.

jjames · ‎09-27-2007

But if the request are duplicated I would be handing out address's at 2 locations?

paolo bevilacqua · ‎09-27-2007

Yes, if you want. Some network has so complicated helper hierarchies that spanning-tree is needed to not duplicate paths. Apparently IOS can do that.

Jon Marshall · ‎09-27-2007

Hi James

Just to add to Paolo's points. Rather than think of active and backup DHCP servers just think of both DHCP servers being active. You can split the scope across your 2 DHCP servers so one serves out the first half of the scope and the other serves out the second half of the scope.

Jon

jjames · ‎09-28-2007

Sometimes the best ideas are the simplest. None of the remotes have more than 15 people so all I need to do is give a 100 to one DHCP and 100 to the other server and I'm covered with plenty to spare.

Thanks!