How to Port Forward for Bittorrent, Azureus Example

Originally posted by snoopinc so all credit goes to him.




Port Forwarding for Bittorrent;
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So your trying to download a torrent and you just can't connect to the torrent, Port Forwarding might help !
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So what is Port Forwarding ?

Port forwarding (sometimes referred to as tunneling) is the act of forwarding a network port from one network node to another. This technique can allow an external user to reach a port on a private IP address (inside a LAN) from the outside via a NAT-enabled router.

Port forwarding allows remote computers (e.g. public machines on the Internet) to connect to a specific computer within a private LAN.

For example:

forwarding port 8000 on the router to a user's machine allows SHOUTcast streaming
forwarding ports 5000 through 6000 to a user's machine allows the use of Unreal Tournament
Modern Linux machines achieve this by adding iptables rules to the nat table: with target DNAT to the PREROUTING chain, and/or with target SNAT in the POSTROUTING chain.

BSD and Mac OS X machines use a similar tool named ipfw. The ipfw tool is likely already running as a built-in part of your operating system's kernel.

Some common caveats with port forwarding include:

the need to forward the packets that come to the router's forwarded port as well as the need to rewrite them so that the machine to which the port is forwarded to can reply to the original source address, which in turn leads to
the inability of the destination (private) machine to see the actual originator of the forwarded packets, and instead see them as if originating from the router

Single Computer
Port forwarding can also be used within a single machine. This is commonly done on Unix-derived computers where port numbers numbered below 1024 can only be accessed by software running as the root user. Running as root can be a security risk, so some people use port forwarding to redirect incoming traffic from a low numbered port to software listening on a higher port. For example, a web server may be listening on a port such as 8080 for traffic redirected from the restricted port 80.
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Lets get port forwarding, This is an Azureus example as there are many bittorrent clients. This example is on a D-Link DI-524 Router. Yours may vary, so visit http://portforward.com/routers.htm and serach your router and bittorrent client to port forward.

Most ISPs block the default port that Azureus uses. So it is a good idea to change Azureus' port number to something other than the default port. Here's a brief walkthrough on how to do that.



In Azureus click Tools in the menu at the top of your screen. Then click the Options link in the menu that drops down.


In the menu tree on the left hand side of this window Connection should be selected. Pick a random port between 49152 and 65535. Then enter that port into the Incomming TCP/UDP Listen Port box. When you are done, be sure to click the Save button at the bottom of the configuation screen.

Open a web browser like internet explorer or Netscape. Enter the ip address of your router in the address bar of your browser. In the picture above the address bar has http://www.google.com in it. Just replace all of that with the ip address of your router. By default the ip address should be set to 192.168.0.1.



You should see a box prompting you for your username and password. Enter your username and password now. By default the username is admin, and the password is blank. Click the Ok button to log in to your router.

Click the Advanced button near the top of the page.

The menu on the left should change. In this new menu, click Virtual Server.


Check the enabled box

(*)Enabled ( )Disabled
Name: Azureus
Private IP: Your IP
Protocol Type: Both
Private Port: 6881
Public Port: 6881
Schedule: Always

We will list a series of lines here that will show you exactly how to forward the ports you need to forward. Azureus requires you to forward the ports you entered above. Go ahead and enter the settings shown above into the Virtual Server menu and then click Apply.

and setup another port forward:

Click the enabled box

(*)Enabled ( )Disabled
Name:Azureus2
Private IP: Your IP
Protocol Type: Both
Private Port: The Port You Choose Between 49152 and 65535
Public Port: Same As Above
Schedule: Always

You should see another page of settings that need to be entered into one of the blank lines on your routers Virtual Server page. Go ahead and enter those settings and then click Apply.

And that is it! You are done!

This post has been edited by wng95: May 13 2008, 03:18 PM