winnt dhcp reservations need help!!!

scorpio5780

Member
Dec 19, 2001
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I have a win nT server and win 2000 prof nodes on a network. I have a set of fixed static IPS for T1 connectoin with me for my lab in the school. I have CISCO catalyst 2900 series switch in the lab. Currently I have set the IPS manually an all th machines and have made a domain in the server to which the clients logon successfully.

Now I want to use DHCP on the NT box to distribure the fixed IPs. I actually managed that. But people outside my lab(from other departments) are also able to take my set of DHCP IPs. So I turned DHCP off. How can I use DHCP and still avoid the outsiders to take IPs from my server. Is there a way in which I can allow a certain set of computers (based on comp name) to take IPs from the server?

I tried doing "reservations" but I read somewhere that they wont forcefully take the IP if its taken by someone else (this case - an outsider). If its not true then do I have to take the MAC addresses of all the machines and put them in "unique identifier" field while making reservations?? Can I do something to the CISCO switch to stop broadcasting??
 

nathank

Junior Member
Jul 11, 2002
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I really don't know a whole lot about DHCP, but I believe you can give out IP's with DHCP by MAC ID for each NIC. I think it just pulls the same IP for each machine every time they boot up. By not specifying the outsiders MAC's in your DHCP table they shouldn't be able to pull IP's.
 

PrincessGuard

Golden Member
Feb 5, 2001
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Can't you just tell the switch not to forward the DHCP ports (67, 68)?

You can't force a client to relinquish an IP address on demand. You can set the lease period really low so that next renewal they'll only have the address for a short time.