Port Forwarding

b) PORT FORWARDING


When you host a server, be it for file transfers or hosting, the software listens for incoming traffic on a specific port range. If these ports are closed, whatever clients that attempt to connect to you will be forcefully rejected, and no connection will be established. Most computer firewall software allows you to add programs to their exception list automatically the first time you execute them and attempt a connection, but most router firewalls do not.

The purpose of this tutorial is to teach you how to open these ports manually. Please note that each router brand and model has a very different kind of interface, so it's impossible to write a universal guide.

The following website http://portforward.com/english/routers/port_forwarding/routerindex.htm has specific, detailed guides for a great number of router models and brands and has a wealth of information on how to open ports for the most popular software. But, alas, it does not cover each and every router in existence. I encourage you to try to find yours on this list. If it is not listed, following a guide for another router model from the same manufacturer should help.
At any rate, I will try my best to explain how to open ports using screenshots from a 2wire 1000hg router as an example.

Step 1:
On Windows 7, open up the start menu, and look for the Search programs and files box.
On Windows XP or Vista, click Run.

Step 2:
Type “cmd” (minus quotes) in the Search programs and files box (Run box in XP or Vista), and press Enter on your keyboard.

Step 3:
Type “ipconfig /all” (minus quotes) in that window, and then press the Enter key.

Step 4:
Make note of the Default Gateway IP, and then close this window.

Step 5:
Open your web browser, and type in your Default Gateway’s IP address. You'll see something like this:
http://portforward.com/english/routers/port_forwarding/2wire/1000hg/1000hg1.jpg

Step 6:
Click the Firewall Settings button  (or whatever equivalent on your router's interface). You'll see something like this:

http://portforward.com/english/routers/port_forwarding/2wire/1000hg/1000hg2.jpg

Depending on your router, you'll see a list with every device currently connected to your router along with their MAC and IP address, and some firewall exceptions if someone else had set some beforehand. Some routers also keep a list of every device that has ever connected to your router, even if it isn't connected at the moment (if you suspect someone stealing your internet connection, you can find out now).

Step 7:
Click the Firewall Settings button. Use the Select a computer box to choose a computer to forward ports to. This box contains a list of computer names that are visible on your network. You'll see something like this:

http://portforward.com/english/routers/port_forwarding/2wire/1000hg/1000hg3.jpg

Some routers feature drop down menus listing every device with varying degrees of detail, while others show a table with each device. Alongside these, most routers also have a predetermined list with the most popular applications preconfigured with the rules necessary to get it running without much hassle. I strongly advise against fiddling around with DMZ Mode unless you know what you're doing or trust whoever decides to connect to your server.

Step 8:
Click the Add a new user-defined application link. You will get a Window similar to this one, regardless of router:

http://portforward.com/english/routers/port_forwarding/2wire/1000hg/1000hg4.jpg

The Application Name can be whatever you want, but it’ll help you identify it in the future if you name it exactly like the software you’re forwarding ports for, or something similar. Just remember that you can't use a name that's already being used by another Exception Rule.

Next you'll choose Protocol: TCP or UDP. Some routers will only allow you to choose one or the other, while others give you a third option to choose both simultaneously.
Depending on the software your opening ports for, you'll need to look at the documentation to find out which one it needs. If it doesn't say which, it's better to open ports for both protocols.
If the router doesn't give you the option pick both protocols simultaneously, you will need to make 2 separate entries for the same port.

Next we have a Port Range. In this section, we'll writing down the port(s) we’ll be opening. If you're just opening a single port, only write it down in the first box and leave the other one blank.
If you're opening, for example, 100 ports between port 1500 and 1600, you write down 1500 in the first box and 1600 in the second.

Everything else can be safely ignored. You can add a Definition or Application Type if you want, but it isn't really necessary.

After you're done adding your port, click Add Definition or Accept or anything that allows you to save your changes.
There are some routers that allow you to make Exception Rules, but don't automatically assign them to your computer/device’s IP. In that case, there should be an option to assign them manually.

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I assume that even though this isn’t a standardized guide, it will at least give you an idea on how to open ports… in the event that your router is not listed on portforward.com, that is. You should be able figure it out by comparing these screenshots to your own interface.
As practice, you should try opening these ports:

- ZSNES
7845 (TCP/UDP)

- KegaFusion
5394 (TCP/UDP)

- OpenKaillera P2P client
27886 (TCP/UDP)

- GGPO
6000-6009 (UDP)
7000 (TCP)

- CSMAME
5805 (TCP/UDP)

If all else fails, install a VPN like Hamachi or Tunngle. It might not be practical, and you will need to convince people to install it to play with you, but it's the only other viable alternative.