Static vs Dynamic IP

Its been a year since I started using the Internet the official way I suppose but I never sincerely tried to understand the concept of IP's or the Internet Protocol. It was only the other day that one of my friend found himself struggling to download a file from rapidshare which incidentally uses the IP of the user to provide the downloads and access is granted to only a single file(no multiple downloads possible) . He uses the LAN connection distributed around some 10 computers and all of them seem to share a single IP. When I checked my IP , I found it changing every instance when I connect myself to the Internet( I use Broadband) . I tried to dig into this as why I was on a Dynamic IP whereas he is on Static one!

Q.) So what is the Difference between Static n Dynamic IP??

Lemme put this direct and simple..

A.) As the name implies Static IP addresses are the same every time you connect. dynamic IP addresses may change each time you connect to the network (e.g. Internet).

When you do NOT need static IP addresses

If you ONLY do things from the following list you do not need static IP addresses.

1. If you browse the Internet.
2. If you send and receive e-mail via an offsite server (the normal method).
3. If you download or upload files.
4. If you use Instant message services or chat services.

When you need Static IP Addresses

You need one or more Static IP addresses if any of the following are true:

1. You run one or more Web server's directly on your site that require external access (from the Internet, or Extranet but not typically an Intranet) .
2. You run one or more E-mail server's directly on your site that require external access (from the Internet, or Extranet but not typically an Intranet) .
3. You run one or more FTP server's directly on your site that require external access (from the Internet, or Extranet but not typically an Intranet) .
4. You run any other service or 'Application' that requires external access (from the Internet or an Extranet). Some Financial Terminal Client applications require that you have a static IP address for licensing purposes.
5. You allow 'incoming' Video Conferencing you may need to use static IP addresses.
   

Its just a brief info. regarding IP's and if you are interested in knowing more then get to wikipedia. Click here

YOUR IP ADDRESS IS: