[GUIDE] - what the hell does a router do.

[Demonic]

As so many people are well confused and don't seem to have a Manual supplied with there brand of Router, I thought I would explain (read boring) what it is and what it does - this may help you understand it a bit more..

ISP
Your ISP assigns you a Internet IP, they can be handled by the router (if you have ADSL one) or Modem/Router set-up. Now most ISP don't really want you to run Servers of any kind so they change that IP a lot, how often depends on your ISP - AOL I think been the worst.

Router
With just a Modem and a computer (one) - you would have a direct IP on that PC but what if you have more then one computer?? Well this is where the Router comes in. It takes the External IP and shares them out to all computers on an Internal Address - with the likes of 192.168.x.x

Any Traffic coming in which you have not told the router about or you have not initiated (Say from a web browser) - gets dropped at the router, this is in a way a form of security if you like. Normally your Router will assign all the right details and a Dynamic IP to each PC.

Making a Server live.
The first thing you need do is Give the computer you want to run any kind of server on a Static IP, to find out the info first, open up a CMD Prompt and type:

IPCONFIG / ALL

Take note of your Gateway and DNS Server Settings. Now alter your network settings on your network Adaptor nd give it an IP in the range you just wrote down, if the router is say 192.168.1.1, then 192.168.1.2 will be fine.

Port Forwarding on the router.
As each router is very different in the web page you do this for, you will have to google this for your router. All you do now on the page which is all about port Forwarding is type in :

Port No (if two boxes for this, this is called a Range, type the same number twice). Now put in the Last digit (in this case 2) and ALL Traffic for that port will be sent to that computer - simple eh!!

DMZ - Beware of this...
What DMZ does (and means) is a Demilitarized zone - in English that means ALL Data for ANY Port will be sent to the IP you have just shoved in there. There is no reason to out this option on whatsoever - you will be scanned and probably hacked if you do this...

Software Firewalls.
One more thing to point out, ANy Software Firewall on the said Server will also need to allow through the data on the port, if this is stopping this, then although all info is getting through your router - the pc will stop it and it wont work. Windows Firewall for example asks you when you first run the Application if you wish to allow it through.

The end..
If you have a Dynamic IP that changes a Lot, then running a server wont happen, you might as well give up now or change ISP's.

 

[mythonline]

great guide.

However, I highly doubt that the reason why the IP changes ^^ but and i could be wrong.

On the other hand, are advantages for it, hackers cannot trace you just by your IP.

 

[Demonic]

There is only so many IP4 Address that can be dished out to every computer in the world and this is why ISP have assigned to them various Banks of IP's which are then shared out as not every computer is on-line all the time. IP V6 will change this WHEN it comes in (might be a while yet). As regards ISP's, most prohibit running any kind of server as this can degrade the service, remembering that most Home Broadband is a shared service.

Most people not even need a router as they have like One computer connected, maybe if they need Wireless. The problem is that also a lot have never read or don't seem to have a Manual supplied so have no idea how to Port Forward, as each brand of router is different, advising someone what to do is not easy.

Understanding such complex things as "What is an IP Address", Local IP, Wan IP and so forth is beyond the average home user, they plug in a router, they can connect to he internet and do what they need, its only when you step into the world of running a server is when they post (A Lot) about the problems - some grasp it, other cannot.