HOW TO: Forward Your Ports

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You need to forward your ports if you have NAT in order to get optimal speeds. This is one of the most common issues people fail to configure when they use BitTorrent. To Find out if you have a NAT issue click on the link below.

http://www.u.arizona.edu/~trw/games/nat_or_not.php

If the above site implies you are using NAT (It would appear that your machine does use NAT msg) , you will need to resolve this by forwarding ports. BitTorrent default use are ports in the range of 6881-6999. (TCP ports) The client starts at the first port in the range(6881) and sequentially tries higher ports until it can find one to which it can bind. So you only need to open as many ports as simultaneous BitTorrent clients you would ever have open.

If you have one of these broadband router/NAT devices (such as the Linksys BEFSR41, D-Link DI-701/704, Netgear RT311, SMC Barricade, 3Com Home Ethernet Gateway, etc.) you will usually need to enter the web configuration of the device. If you're not sure, try


http://192.168.1.1 or sometimes http://192.168.0.1

http://192.168.1.1 (Asus, Draytek, Linksys, Zyxel, Cisco,WooWeb-Pro)

http://192.168.2.1 (Belkin,SMC (some browsers need :88 added))

http://192.168.0.1 (DLink, NetGear,Nexland)


If you are still having problems forwarding ports visit PortForward.Com (http://portforward.com/). It covers most of the routers in the market and provides step by step guide to setup port forwarding.

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Port Forwarding Explained

Ok, you're probably here because you've heard all this talk about "port forwarding" or "forwarding your ports" but don't really know what it all means. By taking a few moments to read everything on this post,, you will have a much better understanding of the concept of port forwarding.

First, we must understand 2 basic networking concepts:

1. Ports
2. IP Addresses


Ports

There are 2 types of ports: physical, and virtual. A physical port is something on your computer, for example, where you would plug something into, such as a printer or a mouse. We are not concerned with physical ports, but virtual ports.

A virtual port is where network and Internet traffic enter and exit your computer. These ports are numbered from 1 to 65535. Webservers, for example, typically use port 80 to communicate. In other words, when you surf to google.com, yahoo.com, or almost any other website, your computer is communicating with the computer running the website on port 80.

When you are using BitTorrent, your BitTorrent program attempts to connect to other users, just as the other users' BitTorrent programs attempt to connect to you. The default port that most BitTorrent programs use is 6881, although many BitTorrent programs allow you to change the port.



IP Addresses

An IP address is a unique number assigned to your computer, or, more specifically, your network card inside your computer. It is what allows most network and all Internet communication. We are going to talk about 2 different types of IP addresses - internal (inside), and external (outside).

Internal IP addresses are not routable on the Internet, only external IP addresses are routable. Internal IP addresses are used on private networks, and are not directly visible from the Internet. In order for a device with an external IP address to communicate with a device with an internal IP address, the traffic must be forwarded from an external device (such as your cable modem) to an internal one (your PC).

The following IP addresses are reserved for internal use (if you have a cable modem, your PC likely has one of these):

* 10.x.x.x (anything starting with 10.)
* 172.16.x.x - 172.31.x.x (anything starting with 172.16., 172.17, through 172.31.)
* 192.168.x.x (anything starting with 192.168.)

If you are using Windows XP, NT, or 2000, and want to see your IP address, do the following steps, and look for the line that says "IP Address......."

* Press 'Start'
* Go to Run
* Type: cmd
* Press 'Enter'
* Type: ipconfig /all

If you are using Windows 95 or 98:

* Press 'Start'
* Go to Run
* Type: winipcfg
* Press 'Enter'


Typical Broadband Setup

http://img69.exs.cx/img69/8789/diagram8no.png

In the picture above, we assume your computer has the IP address of 192.168.1.100. Remember, this is an internal IP address, because it starts with 192.168.x.x. Since it is internal, it needs to connect to something that can see both the internal network, and the outside world - the Internet. This is where your cable modem (or router) comes into the picture.

Let's say someone from the Internet wanted to make a BitTorrent connection to your computer, on port 6881. If they attempt to connect to your computer - which they see as 24.9.258.73 according to the picture above - they are actually going to be trying to connect to your cable modem. Your cable modem is not running BitTorrent obviously, your PC at 192.168.1.100 is. Using the guide at portforward.com, you can learn how to tell your cable modem, "any Internet traffic that is destined for my external IP address (24.9.258.73) on port 6881, should be forwarded to port 6881 on my PC (192.168.1.100).