Port forwarding setup

[MrZalib]

Alright so I have a situation here and maybe someone could redirect me to an informative article somewhere about this because i've read and read and I can't seem to answer this question.

Have a private network here and looking to have services available to outside the lan. As in an external client is trying to connect.

For this port forwarding to work I know the port has to be open and the client has to know both the port and the gateway IP.

However, my question is how can you connect to a specific server on that private network? Say there are multiple computers on this network. How does the router know where to send the packets?

I had one thought that maybe when the server is set up it just automatically listens on that port so whenever a request comes in it just takes it off the routers hands right then and there although I'm not sure if that's correct or not.

Could anyone explain this further? Or point to an article that would explain this thoroughly?

Thanks in advance!! =)

[errorxp]

You probably mean NAT.

[07CobaltGirl]

The simplest way to get there is to set up your router/firewall to forward the port to a specific computer. Say you open up 10.10.10.10:1028 for the purpose, then forward incoming packets bound for port 1028 to computer ABC in the internal network. It's the same way you would run a web/mail/ftp server on an internal network. Just make sure you cover the security bases on the open port or you could be in trouble.

I guess I just ran all around your question. The router and/or firewall listens on the ports designated by its configuration and forwards the packets on that port to where it is told to do so.

Here's a pretty good article on PAT and NAT from Cisco.

How NAT Works - Cisco Systems - http://www.cisco.com/en/US/tech/tk648/tk361/technologies_tech_note09186a0080094831.shtml

[cazo]

Another good place is:
http://www.portforward.com/