linux routing inside a network segment

[Anonymous]

Hi. I've given a project of setting up a firewall in my office.
I have only found documentation for masquerading using one
real IP address and a private network type 192.168.x.x
I did that and it worked, the problem is that I need real addresses,
and my linux box is between the gateway and all my network.
I configured the routing table with the command ip and I can
access the gateway and all the nodes on my network, but it
just doesn't forward.

What am I doing wrong? I someone could just help me, it would
save my job.

Thanks

[wassy121]

sounds like quite the job you have there. Are you using standard port forwarding for some addresses and masquerading for others? For instance:
Comp1 = 65.33.76.33
Comp2 = 65.33.76.34
Comp3 = 65.33.76.35
Comp[4-9] = 65.33.76.36
Comp[10-99] = 65.33.76.37

If you are then you just have to set up different rules in the /etc/sysconfig/iptables (or ipchains depending) that just sort on IP addresses. Like (give me a break this is from memory):
-A -s 0/0 -d 65.33.76.33/255 -j FORWARD_1
-A -s 0/0 -d 65.33.76.36/255 -j MASQUERADE_1

etc.
where FORWARD_1 and MASQUERADE_1 are other chains you set up to send it to certain areas of your network.