DHCP not giving out addresses larger than class C

[epayne]

I have a DHCP server on my network that has a scope of 10.10.1.0 - 10.10.255.0. The subnet mask is 255.255.0.0. I have over 300 machines and my DHCP server (Win2k sp4) will not give out an address over 10.10.1.254. The database is consistant and I have even changed my pool from what was listed above to 10.10.1.0 - 10.10.3.254 keeping the same mask. Does anyone know what is going wrong, I am receiving IP conflicts because I believe the server thinks it is out of address. Any help would be appreciated.

 

[zoeythecat]

Have you tried changing the subnet mask possibly to 255.255.254.0 or 255.0.0.0 ? to see if that may work? I'm not an IP expert or know how IP Addresses get subnetted but we have a similar IP range and our subnet mask is 255.255.254.0 (Not sure how we came up with that). I do know a 10.10 is a Class A network and the subnet mask is usually (or I thought) 255.0.0.0

Just curious if changing the subnet mask may help

 

[DG659]

could it be the the renew time is to short ? ie the dhcp thinks the addresses are no longer inuse . the client is not renewing (maybe off for an extended time).try setting the lease time to 30days

 

[epayne]

I have changed the subnet mask to a /22 with no change. I have also increased my dhcp lease times to infinity and still no change. The only thing I haven't tried is to delete my dhcp pool and start over. If I do that though, won't I get a bunch of IP conflicts as it tries to give out addresses already owned by someone else?

 

[zoeythecat]

Epayne,

No, you should not get IP Address conflicts. When the user logs in the IP Address should get renewed from the new scope. If you do get any conflicts you may need to go to the end users and release and renew the IP Address.