On Mon, Oct 15, 2001 at 11:49:19PM +0200, Imran Geriskovan wrote: > Hi, > > We use DHCP in our LAN. > I wonder if I can block any traffic generated by any > local computer which did NOT get its IP from DHCP server. > (DHCP server and gateway/firewall are on the same box) > > Any ideas?
You could write scripts to add/delete firewall rules when certain "events" happen to the DHCP server. I think ISC dhcp supports this sort of thing. Check the man page. The idea is that when the DHCP server hands out a lease to a certain machine, your script gets run to add a rule allowing 'Net access. When the lease expires, the DHCP server calls your script to remove the rule. Also, if you have a small enough number of machines on your lan, you could build up a list of the machines/mac addresses and use arpwatch to see when someone's changed their IP address. Then go and tell them not to. -- Michael Wood [EMAIL PROTECTED]
