Ubuntu Wiki

What this wiki page will talk about?

In this wiki page you will find some informations about Port Forwading,really usefull to people that are behind a router .The easiest way to imagine Port Forwarding is a combination of routing by port combined with packet rewriting. A convention router examines the packet and dispatches the packet on one of the destionations decided before by the lan administrator, depending on the packet's destination address.I can make an example ,if i have two computers in my lan and in one of them i have a working apache server and i want to make it accessible to outside lan people i can just forward all traffic that will come from outside requesting the 80 port to that pc. Here it is a picture that can help you to understand what im talking about :

So its really important if you have a home server or simply a client program behind a router to use this method to forward every port you want to a specified lan ip.

What i have to do to forward a port?

Ill put now another image that will help you understanding the procediment. To reach this page ,you have only to login with administrator account into your router configuration panel(every router company have got a different panel so this is not the default one for all routers)(to enter inside the panel you will have to use the router ip address(for example 192.168.0.1 or 10.0.0.2 and after the authentication method that every router request before the administration panel ,you will be inside).

This is the panel of conexant routers,as you can see there there are at the end of the page three writable spaces and one choice button :

• Public Port
• Private Port
• Choice button :Tcp/Udp Port
• Host Ip Address

What you have to put in these spaces? Well thats not so difficult ,follow this example. I want to make my web server accessible from outside, first i have to ask me which port will the server/client process use, for our example the correct answer is 80 .So i have to compile the above spaces as it follows :

• Public Port : 80

• Private Port : 80

• Port Type : TCP

• Host Ip Address : Here you will have to put the lan IP of the computer that run the web server

Then press Add Setting. Now you have only to restart your connection and all will work fine, now people will reach your pc from outside without any problem .

I put here some important port numbers :

• Web Server : Port 80

• Ftp Server : Port 21

• Ssh Server : Port 22

• TeamSpeak Server : Port 8767-8768

• HTTPS : Port 443

• TelNet : Port 23

• Amule : Depends on which ports have you put in the amule options

• DC++ Client : Depends on which ports have you put in the client settings

If you want to run a server check before starting the port number that it will use to work, after you will be able to let people join it outside your lan network .