Why do I need to know my IP Address

An IP Address is what identifies your computer ( or router ) on the Internet.  If you need direct access (as in Remote Access or using it as a Server to serve web pages) to your computer from the Internet, you first need to know it's IP Address

Why does my IP Address Change ?

Broadband and Dialup Internet providers issue IP Addresses in two ways, Static and Dynamic.  With a Static IP Address, you get an IP Address from your ISP and it never changes.  If you ever need it, they should be able to tell you what it is.

With a Dynamic IP Address, each time your computer connects or router connects to the internet, an IP address is provided from a 'pool' of addresses that your ISP uses.

When on a Dynamic IP Address, it is not possible to access the computer directly from the internet as its IP Address may have changed.

Some peep-to-peer and remote access services get around this by creating a connection to some 'third' system that remains in regular contact with your machine and learns it's new IP Address when it changes.

There are dyndns services that use this to give your computer a 'name' on the web so that it can be used to host web pages or be reached by other systems even despite having a Dynamic IP Address.

Computers and systems that must be reached via the web on a regular basis benefit from having a Static IP Address as using the DNS system to look up a name and convert it to an IP Address takes time.

Security

Exposing a computer or system to the wider internet involves running services on the computer and opening or forwarding ports on any firewall or router, it should not be done lightly, even using a computer to serve it's own web pages makes the computer and any network it belongs to more vulnerable to attack from the outside.  A full audit of the computer / system should be carried out to ensure that as many measures as possible are in place to protect it.

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