I use RedHat9 as a small office server. I use squid as a proxy, but squid is only a http proxy. I need a nat in order to use msn messenger (audio conversation). I have set it up like this:

sysctl -w net.ipv4.ip_forward=1

iptables -A FORWARD -i eth1 -j ACCEPT
iptables -A FORWARD -o eth1 -j ACCEPT
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE


It's work, but I have two problems:

1. The whole network can access internet without any limits
2. When I type the command "iptables -L" I can't see the line
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE and I don't know how to delete this line


My questions are:
1. What command do I need to allow internet access (through nat) only to one computer?
2. How can I list the nat table and how can I delete the nat records?

iptables -t nat -A POSTROUTING -s 192.168.0.2 -o eth0 -j MASQUERADE
iptables -t nat -A POSTROUTING -o eth0 -j DENY

assuming u want to allow only computer 192.168.0.2 to be nat'ed.

the command to see the nat table is: iptables -t nat -L