Static IP, What is it and do I need it?
By Shane of PcWinTech.com

Some users can get confused on the term static ip and where to set it up and if they even need to bother with it. So I will try to explain what it is, why you may need it and if it is worth the trouble.

First what is a static IP.

When your computer gets on the internet (same for your PS3, Xbox, and so fourth)  it gets a IP address from the router/modem.
This IP address is the information Windows needs to know how to communicate with the network and the internet. The ip address you get is normally automatic.

Well when you set up a port forwarding rule, the rule points to your local ip or to the ip of the machine you need the connection to go to. Well since getting a ip address is automatic then the next time it renews its ip it may get a new and different one (Example: your ip was 192.168.1.134 but is now 192.168.1.145). Normally you never see this and you never need to worry about it, but when port forwarding you do. And since the port forwarding rule is pointing to your old ip the rule will no longer work.

So to keep this from happening you set the IP information yourself. Since you are now setting it to static (never changing) your ip will never change and thus your port forwarding rule shouldn't break.
But keep in mind there are both pros and cons to this.

Pro's:
#1. The only real pro to this is your IP wont change and thus you don't have to worry about the port forwarding rules not working (Only good for computers that don't connect to other networks).

Con's:
#1. If your on a laptop and travel (You connect to other networks) you will need to turn your IP information back to automatic, otherwise the IP info may not match any other wireless network you connect to (like at a cafe) and you wont be able to get on the internet.
#2. Some routers (I have seen a few) don't play nice with static IP's, since the router is the one that handed out the IP when it was set to automatic. Some routers have been designed to auto handle things better. If the computer doesn't show up as have received an IP from the router the port forwarding rules wont work. The Thomson brand routers are some I have seen do this.
#3.  Some users miss understand the need for a static IP and try to set there internet IP to static, which is a big no no unless your internet service provider tells you other wise.

So as you can see it all depends on what computer your on, what the setup is and if it is even really needed. I have made tools to help users with this process, both in the Simple Port Forwarding Program and the Simple Static IP program.

I hope this helps and answer any questions.

Take care!
-Shane