DHCP error

[JBruyet]

Hey all,

I’m trying to alter the DHCP configuration on my NT server so I can get another one on my network, but every time I try to make a change to the range I get the following error message: “The range is extended less than the specified backward extension. Extend the range in integral of 32 addresses.” I’ve tried using multiples of 32 for the starting and ending addresses in the range but I still get the same error message. I checked the Microsoft web site in case I was missing something, but even when I use the addresses in their examples I get the error message. Some of the address ranges I’ve used are: x.x.2.32-x.x.2.64, x.x.2.32-x.x.2.96, x.x.2.16-x.x.2.80. The original range is x.x.2.16-x.x.2.254, but if I input x.x.2.16 for the first address in the original and try to save it, I still get the error message. I’m baffled.

Thanks,

Joe Brouillette

 

[SteveTheGeek]

What's the subnet masking look like?
-Steve

 

[JBruyet]

They're all 255.255.255.0, and no routers to deal with on this end.

 

[SteveTheGeek]

Looking at M$'s "help" it looks like they're saying you need to be 32 lower than what you've got now - which is not initially possible in the subnet, so you might try x.x.2.48 as the start address. I don't have an NT4 DHCP server handy so I can't see exactly where you're talking about, but I gather you're trying to make the range smaller? Perhaps leave the start where it's at and set the end to x.x.2.221, or if that doesn't work the other option would be to simply set an exclusion range on your current DHCP server and have the new DHCP server use that range that the old one has excluded.
-Steve

 

[JBruyet]

I've tried x.x.2.48-x.x.2.80 and x.x.2.48-x.x.2.112 but I still get the error. I've tried having the start address as a multiple of 32, the end address as a multiple of 32 (so the range was a multiple of 32) but it's still not working. I HAVE to be missing something simple but I don't know what. Any other ideas, rather than admitting my defeat to the server and using the exclusion range instead? :^)

Thanks for the help,

Joe Brouillette

 

[member 141630]

I've had this before under NT when trying to shrink a DHCP scope range, and found the only way was to delete the entire scope and recreate it... doesn't take very long... (just remember to write down any static reservations and exclusions before you kill the scope!)

 

[JBruyet]

Hey F1lby, I thought about doing that but I had this mental image of not being able to set any kind of scope afterwards. Now I think I'll give it a shot since I'm out of ideas.AND, since what I'm doing IS shrinking my scope (like you mentioned) I'm going to trust that since it worked for you it'll work for me too. And if it doesn't work, the local fast food joints are always looking for help.

Thanks all, I'll let you know how it works out.

Joe Brouillette

 

[JBruyet]

Yep, F1lby was right. I removed the existing scope and then created the new scope and everything did what it was supposed to do. I still would like to have been able to simply "tweak" the old scope, and if anyone has an idea that hasn't been mentioned in this thread please let me know. Like the bank robber said to Dirth Harry, "I gots ta know!"

Thanks again,

Joe Brouillette

 

[member 141630]

The only way I found to play with scopes in NT is to build a BIG scope and add exclusions to it which can be removed / added @ a later stage....

 

[ErikButler]

I have had a problem with DHCP on nt4 as well when tweaking the scope and it is irritating. Here is how i fixed my issue even though it makes no sense.

Old scope 172.20.6.1 - 172.20.7.254
tried changing to 172.20.3.1 - 172.20.4.254 and it gave some bogus error on overlapping a scope

so what i had to do was change the range on value at a time.
First change was the scope to
172.20.3.0 - 172.20.7.254 and applied the change and it liked it.

Then had to change the ending ip from 172.20.7.254 to 172.20.4.254 and it was ok with this.

now the scope is 172.20.3.1 to 172.20.4.254 and it likes it just fine.

Note this is the same range as I tried the first time that it complained. Dont ask me why its just on of Microsofts hidden features. Thanks
Erik Butler
2000 MCSE
erikbutler@centurytel.net