Port Forwarding

[J_Th4ng]

After the issues that some of us had hosting Borderlands sessions, I thought it would be worth posting this link here.

http://www.portforward.com/english/routers/port_forwarding/routerindex.htm

Basically, this is a site that provides detailled instructions on how to enable port forwarding for many different makes and models of router, as well as firewalls. There are also links to games and applications, detailling which ports need to be forwarded. Pretty useful, I think...

http://www.portforward.com/english/routers/port_forwarding/routerindex.htm

[SlipperyDuck]

Good find there boss!

Important to notes, i think, that you should understand below:

When things are flowing to and from teh internet, it works like this:

Friend = from the internet ---> will first arrive at your ADSL modem (and the ADSL modem's firewall), if he/she is let through(coz of the rules/port-forwarding), will then need to go through your Windows Firewall software (you will need to have a rule to allow this in windows firewall or your 3rd Party firewall that you have installed).

You = on your computer ---> will first have to go through your own windows firewall (with rules that allow it), then through your ADSL modem firewall (in general though the ADSL will automagically allow all things OUT TO the internet).

IOW: For two way communication, you have to have both Windows Firewall software set to accept as well as your ADSL modem/Firewall set to do the same.


NERD ALERT, EXPLAINATION BELOW:
You may be wondering how this all works.
You’re ADSL router connects to the DSL network and gets an INTERNET IP address. When you connect to the ADSL router, you’re using a PRIVATE IP address.
When YOU connect to the internet, The ADSL router takes your PRIVATE address and changes it to the INTERNET one and makes the request for the webpage, or connection to the BF2 account server ON YOUR COMPUTERS BEHALF. This is called NAT (network address translation, it’s also call masquerading).
By Default, the ADSL modem will NAT all your outbound requests to the internet and will do it for a number of PRIVATE IP addresses, or multiple computers/devices on your private network @ home/office. The ADSL modem remembers each session and assigns a session number etc etc to keep track of what it’s doing and which IP address is making which connection.
When it comes to requests coming FROM the internet, the ADSL modem has no idea which machine to NAT the IP ADDRESS to. (Do I send this to the Laptop on 192.168.0.101 or the PS3 on 192.168.0.103???)…. Make sense?
This is where port forwarding and DMZ comes in to play.

Here’s some examples of ports, so you can get a brief understanding:
When accessing a web page you machine uses port 80, https webpage - 443, Steam login uses 27015, etc etc.
When you set up port forwarding, you can have an Incoming port number forwarded to a specific PRIVATE IP address.

Let make a ridiculous example just for explanations sake:
Let’s say your Computer is the STEAM login server. Your friend needs to login to steam and clicks login. His/Her steam login client tries to connect to your INTERNET IP address on port 27015.
Your ADSL Router receives the request on port 27015. Without port-forwarding, it has no idea which PRIVATE address to change to and send it on to so it would just drop the request.
If port forwarding for 27015 was configured on the router to send to 192.168.0.102, then it would happily send the request through and your friend would successfully log on. (if your Steam Login server firewall permitted 27015 in and out – mind you).

Anyway, I think you get the idea.

Last note:
DMZ is a different story. DMZ sets ONE IP ADDRESS to forward ALL inbound requests to, it doesn’t affect your outbound requests from all your Local machines (*remember that clever session control thing on the ADSL modem), only the INBOUND from the internet. In a DMZ mode, you better make sure that your machine you forward to has a good firewall.

[Paul]

Ok Lee so the problem, I had last night where I couldn't host a game because it was blocking you guys. If I "enable" DMZ then it will be cool?

[SlipperyDuck]

It's DMZ or port-forwarding.
I wrote something in the Borderlands thing about which ports to enable in ESET firewall.
Those same ports need to go into port forwarding <-- if thats the method you choose.
Else, DMZ will just forward all of them...bit easier, just your firewall needs to be secure.

[Paul]

OK I will look at the other thread, the only firewall I have is my windows one and the built in Router one,