DHCP problem HELP!!!!

[wesleyw]

Created DHCP on a new server.

Setup the scope to be

192.168.0.1 - 192.168.7.254

Subnet 255.255.248.0

DNS setup correctly and the gateway.

I then excluded 192.168.0.* and 192.168.3.* from the range. When I renew the address on a pc I get the addrss of 192.168.1.0 which I know can't be used as its the subnet mask address but it still manages it how can I stop this bl**dy thing from messing up? I know you can exclude 192.168.*.255 but it doesn't allow 192.168*.0 to be excluded!

Wes

[ChrisH]

I have had issues like that before and I am sure it let me exclude them. There must be a better way to fix it though.

Maybe I did it just for the single address.

[wesleyw]

Actually just thinking if the subnet mask is 255.255.248.0 then the subnet mask IP address would only be 192.168.0.0 with the 192.168.*.255 as broadcasts? So 192.168.2.0 is valid?

CCNA people out there is this correct?

Wes

[Geoff]

a .0 address is valid. It will cause interesting problems on older buggy TCP/IP stacks (mostly Print Servers and Microsoft stuff). If in doubt avoid handing out .0 addresses. .255 addresses have similar issues.

I suggest you break down your IP range into several class C scopes and override the netmask DHCP option.

[wesleyw]

Would that be one superscope then 0.* 1.* 2.* etc..? How would I override the netmask DHCP option?

Wes

[Geoff]

Just had a look here. $%^$* inflexible MS DHCP server. You can't do it that way with it. So that leaves you with the following options.

1) Create one big scope. Either do not include the problematic IP's in the IP range or use reservations to exclude them.
2) Create serveral smaller scopes. Use a router to route between your seperate IP ranges.
3) As above, but instead of using a router, use static routes to a smaller scope that holds your servers.