[CentOS] iptables questionson CentOS

Hi,

I know these are a few iptbales questions. NOT CentOS, anyway, I am running a firewall on centos 5.x.

If you can response, it would be fine.

I want to add a SNAT rule for one user in LAN to access one particular destination on the internet.

Let's say www.centos.org

I added the below rule. But . it does NOT work Pls assume 1.2.3.4 is the real ip of the firewall. ip address 192.168.101.230 is the client PC

iptables -t nat -A POSTROUTING -o eth0 -s 192.168.101.230 -j SNAT --to-source 1.2.3.4 -d www.centos.org

Any idea to achieve it?

And Also,

the below rule excludes 1 ip. it works fine.

iptables -t nat -A PREROUTING -p tcp -m multiport -s ! 192.168.1.9 --destination-port 80,465,995 -j DNAT --to-destination :3128

I want to exclude about 4 or 5 ips.

let's say 192.168.1.11, 192.168.1.19, 192.168.1.20,192.168.1.25

Is there a way to do it?

Hope to hear from you.