Dual(backup) DCHP servers in 2003 AD Best practices?

[markm75]

I have 2 DHCP servers in my domain, they happen to be on the only 2 DCs (Global catalogs too) in our domain of 5 servers... I guess these could have been on member servers but they are on DCs (which also happen to be the DNS servers as well)..

Any recommendations on splitting up the single segment we use (IE: .100 to .254 etc).

The way I have it now, I have a scope on each server.. one server, serverA has scope set going from .100 to .150 or so.. the other, serverB has scope from .151 to .253.

I setup reservations on both servers (they match on each server).. I'm not using exclusions, just reservations that fall within those ranges.

I've heard the 80/20 rule or even 50/50 are best to be used, but even more recently someone suggested "overlapping" the two scopes, with identical exclusions on each server. This idea made no sense to me. I also recently had a glitch where for some reason, the second dhcp went down and any new machines or rebooted machines couldnt get an IP address, even from the first one (I also have VPN on RAS set to use DHCP, but with only 40 machines in house and 1 or 2 vpns outside, I didnt think this was the issue).

So I'm seeking a poll of advice on which way most are doing their 2003 domains DCHP wise.. 50/50, 80/20, overlapping (explain if so, still dont get this method), another way... installed on a DC/domain member etc..

Thanks

 

[WhoKilledKenny]

The way you have it configured works, I have seen DCHP setup many different ways. I think it is just a matter of taste. My prefernce is to do the following:
Recuirements:
1. 1 - 10 reserved for network equip.
2. 11 - 54 reserved for static IP Devices
3. 50/50 scope option.

On both DHCP Servers create a scope for the subnet, I use the whole range - X.X.X.1 thru X.X.X.254

On both scopes I create exclusion ranges of x.x.x.1 - x.x.x.50

50/50 scope -
On DCHP1 I would create an exclusion of X.X.X.154 thru X.X.X.254 (block of addresses that DHCP2 assigns)

On DCHP2, create an exclusion of X.X.X.55 thru X.X.X.153 (Block of addresses that DCHP1 assigns)

I like the fact that you put reservations on both servers (good documentation). Clients with reservations will not give up their IP address if the DHCP server is down.

second dhcp went down and any new machines or rebooted machines couldnt get an IP address[/qoute]
This would concern me... as it stands (when both DHCP servers are online) do you see addresses being leased out from both servers? - you should. If not check with your Network team to make sure that the IP-Helper address (Cisco)is routing to the IP addresses of both DHCP servers.

 

[markm75]

Thanks for the info..

Maybe thats the one thing that could have caused the problem, as I dont have mirrored exclusions as you mentioned on each server...

Funny (to me at least).. you say ask our network team .. actually where I work I'm a one man show.. 6 servers, 7th offsite, 40 computers (35 users).. so its just lil ole me We only have a Symantec Gateway 460r router.. so I know thats not the issue..

Perhaps it was in fact my lack of exclusions on each.. though that may not explain why a brand new out of box workstation couldnt latch on that day, when serverb was down.

Cheers