How to access workstation behind a router with external IP

Posted on 2003-03-08
Medium Priority
Last Modified: 2013-11-29
Hi network experts,

I just need to know how can I communicate via a client-server application with a machine(server side of the application) that is behind a router. I have the external IP of the machine but it only work when we set the machine as the default DMZ server.

My network knowledge is very limited and I'm having an hard time to figure out how can I achieve this. Can it be done via a tunnel or with the route command under DOS? Wath is the most common solution expert use to resolve this kind of problem? I just need a little track to get a good idea.

Any comment will be very appreciated, thanks in advance.

Question by:JeromeCaQcMtl
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Accepted Solution

antonsigur earned 200 total points
ID: 8095155
Assuming the router is in NAT mode.

You will need to know the servers port. (let's say you are running a ftp server on port 21)

now you neet the servers ip. let's say it is

let's say your external ip is

Now you neet to add a rule on your router, you need to port forward from to

That is, if someone tries to access on port 21, his ip packages are directed to port 21 on

You'll find this options somwhere on your router box, probably undir NAT-services, port forwarding or simmilare.

Probably you must select range if ip's , so you select from port 21 to port 21. You must select protocol to, UDP or TCP or?

hope this helps

Author Comment

ID: 8095206
Tanks a lot antonsigur

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