The IP address looks like it refers to a single computer (actually it would be a single network interface — a single computer might have multiple wired and/or wirelss network cards and each would have its own IP address). But that’s not all it can do.
For a network card, an IP address is a specific defining set of numbers. The complication is that a network has a bunch of IP addresses — the netmask is used to say which of those computers are really part of a network — which computers you want to have the ability to talk to each other and/or your router and ISP.
So, to define the home network that might have up to 254 computers on it, we would write 192.168.1.1/255.255.255.0 .
The 255s (which is 8 bits, all of which have a value of 1) in the network mask specify that each of the bits that make up the 192, the 168 and the first 1 are significant and required to define this network. The 0 in the last position of the network mask says "anything is ok here, any value here is part of the network."
Finally, back to my visitors, IP addresses are pre-defined to different parts of the world. There are different entities in different parts of the world that assign the IP addresses to ISP’s and other companies who need blocks of addresses on the Internet.
Most of us use IP addresses that are officially assigned to our Internet Service Providers. Some of us have static addresses assigned (ones that never change), while others have dynamically assigned addresses which "lease" to us for short periods of time (the duration of a phone call, 24 hours, etc.). If we stay connected via cable modem or DSL (or in a private network with its own DHCP server), we usually never know that a lease has expired and been renewed — that’s a "computer detail" that we as humans normally don’t have to worry about.
So, finally back to the country list, since IP addresses are required for communications to actually work on the Internet, and since IP addresses are assigned in known blocks to countries and geographical businesses and ISP’s, it is fairly easy to back-track and see from where a visitor came.
Email addresses, on the other hand, don’t tell a lot. This is because so many people internationally have gmail.com, yahoo.com, hotmail.com and such addresses can’t definitively be identified by country.
Other domains like cox.net and bellsouth.net, both of which I know are US entities) are identifiable by country, as are email addresses ending in a 2-character country code, such as .uk, .au, .nz, .de, and .no. I still enjoy seeing the country codes in emails, since they are easier to notice.
What’s the value in knowing the countries? For me, the curiosity and the thrill of having an internationally known newsletter and web site.
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Hi
I am a volunteer Computer teacher – teaching Seniors how to use PCs and explaining in simple terms how PCs, networks and Internet works. When I explain IP addresses, I use the telephone (fixed or mobile) analogy – people/companies/organisations have names (URL equivalent) but you can’t dial them using their name so you look up telephone book (DNS equivalent) to get their telephone number (IPAdress equivalent). The telephone number is unique to that particular person/company/organisation otherwise when you dialled the number the telephone/mobile network would not who to connect the call to. The same applies to IP addresses they have to be unique to an individual connection to Internet otherwise the computer network would not know where to send data to.