DHCP server tracking

[nordick26]

Hello,

is it somehow possible to configure a DHCP server tracking and to backup it by Cisco DHCP solution. To be more clear, I would like use Cisco DHCP feature on the router to act as a backup DHCP in case of my DHCP server (or link to it) fails.

Thank you in advance for any helpful opinion.

[nordick26]

Don't you have any ideas or experience, which could solve this problem? I was thinking about ip helper-address, but the problem is, that it's the router who take the role of the DHCP even the primary DHCP server is running. Is it possible to set up some kind of delay or tracking feature?

Many thanks !

[Pavel Bykov]

In our very large enterprise environment with over 100 DHCP servers even Microsoft experts set it up for manual redundancy.

Meaning, we have 2 ip-helpers on every vlan interface always pointing to two DHCP servers. One of the servers has scopes Disabled, and another Enabled. When primary server fails, administrator Enables scopes on the backup servers.

Cisco ip helper constantly translates broadcasts into unicasts to both destinations, so there is no need for changes there.

I would like to know if there is automatic solution, but i don't have much hope. It could probably be done with two DHCP servers with both active scopes, and then configure conditional routing to one of them based on the availability.

[nordick26]

slidersv: Yes, concerning two DHCP servers it's clear, but to save resources, how could I use only one server and for the second one (only to use in case of WAN link failure at the branch office) use the DHCP feauture on Cisco routers? Do you thing that it's somehow possible? Or it's only my optimistic speculation? :o)

[nordick26]

Any other ideas please?

Thanks