DHCP redundancy 1

[DanielUK]

I've been reading a post on another site regarding DHCP redundancy which might fit as a solution for our LAN. I have two Win2k DCs and want redundancy whilst sharing the same address pool, reservations, scope etc Would this work:

2 DHCP servers. each server has a scope of say 192.168.100.1 - 192.168.100.254
DHCP server 1 excludes the second half of the scope say from 127 to 254
DHCP server 2 excludes the 1st half of the scope 1 to 126

both DHCP servers can have the exact same server and printer reservations.
activate them both and run them in Parallel
so if one server goes down - no problem. you still have plenty of addresses in the pool to pass out and all your printers and computers that need specific IP addresses will get them without any problem because both servers will have the needed reservation. and you don't have to worry about them conflicting with each other since though they are operating out of the same scope they aren't working with the same address pool.

Basically, because of new software we are implementing, it requires fixed IPs for most of our clients. I know I can manage fixed IPs via reservations, but need the same reservations to be dished out by the second DC if the primary goes down. The above seems like an answer to this. Any comments?

 

[nsantin]

You want to create a superscope, that way both DHCP servers are aware of the other.

Also, post in this forum:

http://www.tek-tips.com/threadminder.cfm?pid=950

 

[DanielUK]

Thanks nsantin, forgot about the DHCP specific forum, sorry!

I'm probably getting confused here but do I set up one superscope on the PDC to include the whole address range, reservations and exclusions or do I set it up on both DCs?

Thanks

Dan

 

[nsantin]

Setup a superscope for both DHCP servers for the same range, then set the exclusions by server. Typically an 80/20 rule is used. (80% available addresses on 1 server, 20% on the other)

Here is some reading on superscopes:

http://technet2.microsoft.com/WindowsServer/en/library/3967ddab-0b28-4959-8b4d-3052c178731b1033.mspx

 

[WhoKilledKenny]

Sorry to barge in. I'm not sure a superscope is what you are looking for. I didn't see where Daniel was asking to use multiple subnets on the same network segment?

If a client has a DHCP reservation, and the DHCP Server goes down, the client(that has a reservation) will not give up his IP Address. Nor, does the client's reservation time out like regular DHCP leases.


Jesse Hamrick

http://www.powershellpro.com