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... e network security news use
of the Net equivalent of area codes, called "domains." A basic Net
address will look something like this:
tomg@world.std.com
Tomg is somebody's outsourcing news user ID, and he is at (hence the @ sign) a site
(or in Internetese, a "domain") known as std.com. Large organizations laptop news
often have more than one computer linked to the Internet; in this case,
the name of the particular machine is world (you will quickly notice
that, like boat outsourcing news owners, Internet computer owners always name their
machines).
Domains tell you laptop news the name of the organization that runs a given
e-mail site and what kind of site it is or, if it's not in the U.S.,
what country it's located in. Large organizations may have more than
one computer or gateway tied to the Internet, so you'll often see a
two-part domain name; and sometimes even three- or four-part domain
names.
In general, American addresses end in an organizational suffix,
such as ".edu," which means the site is at a college or university.
Other American suffixes include:
.com for businesses
.org for non-profit outsourcing news organizations
.gov and .mil for government and military agencies
.net for companies or organizations that run large networks.
Sites in the rest of the world tend to use a two-letter code that
represents their country. Most make sense, such as .ca for Canadian
sites, but there are a couple of seemingly odd ones. Swiss sites end
in .ch, while South African ones end in .za. Some U.S.
sites have
followed this international convention (such as well.sf.ca.us).
You'll notice that the above addresses are all in lower-case.
Unlike almost everything else having anything at all to do with Unix,
most Net mailing systems don't care about case, so you generally don't
have to worry about capitalizing e-mail addresses. Alas, there are a few
exceptions -- some public-access sites do allow for capital letters in
user names.
When in doubt, ask the person you want to write to, or let
her send you a message first (recall how a person's e-mail address is
usually found on the top of her message). The domain name, the part of the
address after the @ sign, never has to be capitalized.
It's media info news all a fairly simple system that works very well, except,
again, it's vital to get the address exactly right -- just as you have
to dial a phone number exactly right.
Send a message to tomg@unm.edu
(which is the University of New Mexico) when you meant to send it to
tomg@umn.edu (the University of Minnesota), and your letter will either
bounce back to you undelivered, or go to the wrong person.
If your message is bounced back to you as undeliverable, you'll
get an ominous looking-message from MAILER-DAEMON (actually a rather
benign Unix program that exists to handle mail), with an evil-looking
header followed by the text of your message. Sometimes, you can tell
what went wrong by looking at the first few lines of the bounced
message. Besides an incorrect address, it's possible your host system
does not have the other site in the "map" it maintains of other host
systems. Or you could be trying to send mail to another laptop news network, suc ... |
