PC Tips & Tricks

When you are on-line to the Internet, you have a "real" "IP address" assigned to you, or to your NAT/router, assuming you have one.  This address is like a telephone number, but one which can typically change [unless you subscribe for a static IP service] every time you dial up, or every time you power cycle your modem or router.  It is OK if it changes, because your ISP knows how to find you no matter what IP address it assigns to you. The IP addresses are really just borrowed from your ISP when you are on-line. The Internet authorities have also reserved some IP addresses which are not supposed to be used as real, and which are to be used by "private" networks. This is kinda like a "room number" as opposed to a street address.  The post office doesn't know which room at the address the mail goes - you have to decide that.

Remember that an ISP can track, after the fact, which username is associated with an IP address, by interrogating the "RADIUS" logs which record when you sign onto the ISP, and what IP address you were assigned.  If you have a cable modem service, they can associate the MAC address of your cable modem or your PC NIC with the IP address, so much the same effect is achieved. The IP address looks like:

This is a very good thing for the health of the Internet.  When another ISP reports to abuse@yourisp.com that you are becoming a terrorist, they can look in their logs for the time of the infraction and find out which user had that IP address.  More and more, ISPs are terminating ill-behaved customers.  Unfortunately the customer just goes and signs up with another ISP.  There needs to be a blacklist of people who get kicked off ISPs, sort of like a credit report for Internet usage!  There are  already so-called "black lists" for those ISPs which seem to host too many SPAMmers.  Unfortunately these people hide behind fake IDs in order to do their trash.  They are very hard to trace.

You can check your IP address on various sites like on http://whatismyipaddress.com/ and many more just google it.