I'm trying to figure out, if it's possible to execute command when dhcpd server makes new lease to clients. I've been looking all over, but couldn't find any info on this.
My goal is that when new dhcp client gets ip address on lan, I'd like to update my firewall so that new ip # can have internet access. I would also check some other parameters while executing script (mac address..), so that I have full control of who is allowed to go out to internet.

My RH9 server has dhcpd server as well as it is a gateway to internet, and clients are windoze boxes.

Any suggestions?

I should probably ask this question over at the dhcp groups, but since this forum is very dynamic, there may be someone that has a suggestion.

Regards

you can allow access to the entire subnet in the dhcp lease. So you won't need to update your iptables each time a new ip is leased.

I know that, but I'd like to be on the safe side, and be in control

Idea ...

Run a script from cron which will periodically ...

Check for the last entry in the dhcpd.leases file
Compare with your list already approved ips
If new, insert this new ip entry into your list of approved ips
Re-run the firewall script