Reaching internal computers through the external ipaddress inside private network

Hi

I've been trying to solve this problem for quite some time now, but i can't really figure out how... Here's my current setup:

                              _ my computer (10.0.0.3)
                             |
internet - iptables gateway -|- my server(web, mail etc) (10.0.0.2)
            (212.181.43.20)  |
                             |_ a bunch of other computers (10.0.0.x)

Basicly, what i want to do is to allow 10.0.0.3 to access my external ip through the internal network, so i can reach, say, the webserver at 10.0.0.2 through 212.181.43.20:80. I've tried some different iptablesconfigurations around, but it hasn't been leading anywhere near success.

Any ideas?

Thanks,
Christopher

Christopher Abrahamsson sighed and wrote::

I believe you firstly need to do a NAT prerouting and then after the forward lines, you need a POSTROUTING NAT command. Here's my stab at this, given your situation:

iptables -t nat -A PREROUTING -i eth1 -p tcp -d 212.181.43.20 \
               --dport 80 -j DNAT --to 10.0.0.2

#not too sure if the next line is needed. iptables -A FORWARD -i eth1 -p tcp --dport 80 -j ACCEPT

iptables -t nat -A POSTROUTING -o eth1 -p tcp --dst 10.0.0.2 \
           --dport 80 -s 10.0.0.3 -j SNAT --to-source 212.181.43.20

Mind you, I think the last line above, the --to-source should be pointing to your gateway's internal IP and not the external one. If your gateway's internal IP is 10.0.0.20, then the above should be:

iptables -t nat -A POSTROUTING -o eth1 -p tcp --dst 10.0.0.2 \
           --dport 80 -s 10.0.0.3 -j SNAT --to-source 10.0.0.20

Can someone point out if I got the above correct?

Edmund