How Does E-mail Work?
How Does E-mail Work?
E-mail is sent in the form of an Internet Protocol Packet. Your computer divides the e-mail message into smaller-sized chunks of data (packets) which are then sent out over the Internet. Almost anything can be put in an IP packet: e-mails, the text from a book, lines of code from a computer program, pictures of your kids, or sounds and music from your favorite video. IP packets are what travel across the Internet.
These packets not only carry the chunks of data (like an e-mail message), but they add on some additional information, too. A header, which is tacked on to the front of the IP packet, contains this extra information. The header contains the address of your computer which is sending the data (called the source address), the address of where the data is going (the destination address), and a number that verifies that nothing got lost along the way (called a checksum).
When your e-mail leaves your computer network (AOL for example), a router sends that message towards the destination. And towards means just that. Your computer network is not directly connected to your friendâs computer network. There are actually several networks in between. (The Internet is a network of networks.) The router sends your message in the right direction. At the next network, your IP packet encounters the router on that network. It looks at the destination address and forwards it on towards the next appropriate network. Your IP packet will go through several different networks and routers before it finally reaches its destination even if you're sending it to your next door neighbour.
What makes IP packet routing so amazing is how quickly these steps are accomplished. How long does all of this take? An IP packet sent from New York to Los Angeles, stopping at every router along the way, could take as little as two-tenths of a second to make the entire trip coast-to-coast.
The routers know where to send the email by the destination address that you input. The destination address is the e-mail address of the person you're sending the e-mail to.
Just like everybody has a unique U.S. Postal service name and mailing address combination, each user on the Internet has a unique e-mail address - a name and address combination which nobody else has. E-mail addresses are in a different format than regular mail addresses, yet they tell a large amount of information in a small amount of space.
President
The first part of the e-mail address is that person's username, in this case, President. When someone logs on to the network, they must identify themselves by keying in their username, which has been set by the network administrator.
@
There can be people on the Internet with the same username (just like there are many John Smiths in the phone book) The @ symbol says that this username is located at the following computer address - the username has to be unique at that computer address. Everything that follows the @ sign is called the domain name.
Whitehouse
This part of the e-mail address is called the host name (the host name is part of the domain name). It identifies the name of the computer which this person is connected to.
.gov
The final part of the domain name - and of the entire Internet address - is a code indicating either the type of organization or the location of that host computer.
Following is a list of the seven organizational domains which you will find on the Net:
com ....Commercial company
edu.... Education Institution
gov .... Government
int .... International Organization
mil .... Military
net.... Network Gateway
org .... Nonprofit Organization
Some computers use geographical domains, which indicate its location rather than the function of the computer. For example:
au Australia
ca Canada
it Italy
mx Mexico
us United States
uk United Kingdom
