[LARTC] Need advices setting up a Proxy arp and DHCRelay router

[Tiago Bruno Espírito Santo Silva]

Hello Every One!

I need some advices with a problem i have.

    I'm working in a room from a department where the connection to the 
Internet is given by a NAT router and the IPs are given by a DHCP server.
There are no firewall in the department so i'm trying to make a Firewall 
and a traffic shaper for all the PCs in my room.
Because i don't have access to the DHCP server from my department and i 
can not use a NAT in my room because all the IPs have to be public in 
all the department, i have thought in use a Proxy ARP router with a 
DHCRelay...BUT there are problems like i can´t predict what are the IPs 
given by the DHCP server and i can not make routes in the router to say 
that the IPs X, Y and Z are behind the router.

So..It is possible to have a proxy arp router with a dhcrelay without 
knowing what are the IPs given to my firewalled computers?

The information i need i can see it when i make execute "arp -a" it 
lists the MACs IPs and the device where they are. I add the routes by 
hand, but How can i use it to update automatically the route table?

Other problem, the DHCRelay works fine and it forwards all the DHCP 
requests/replays BUT i don't know why the winXP clients DENIES the 
replays and don't accept the IPs given. With the Linux BOXs there are no 
problem. I saw it with ethereal.

Thanks in advance.
Tiago