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INTERNET BASIC

PID, IP, Email and Host Names

Question: What is a PID, a hostname, an e-mail address, and an IP address?

Think of it this way:

PID

A PID (Personal IDentifier) is a name assigned to YOU which is unique on the University of Alaska network (UACN). The PID identifies YOU, and is usually based on your name. You have to have a PID to be given authorization to access the network; you also have to have a PID to receive mail on the campus or DMW mail server.

==> An example of a PID is "tnelc" or "tselc".

On the University network system the initials each have a meaning.
T=Sitka (J=Juneau)
N=Staff
S= Student
and the ELC would be your three (or more) name initials.

On the University network system USERNAME is a word often used when asking for your PID.
A USERNAME is asked for is each time you logon to Kerberos and ACAD1. ==> An example of a USERNAME is "tnelc" or "tselc".

IP Address

An IP (Internet Protocol) address identifies YOUR computer; your IP address is unique on the Internet. You need an IP address so that information which is being sent to your computer will know where to go.

An IP address is usually expressed as four 1-3 digit segments separated by periods (called dot notation). The meaning of each segment depends on the type or "Class" of the address, but you can think of it in general as identifying progressively narrower scopes of location, like your street address at home; e.g., in the example below, the 17 is like your house number, the 28 is like the street name, the 173 is like the city, and the 128 is like the state. This is NOT how it really works, but it is a useful analogy.

==> An example of an IP address is 128.173.28.17

Hostname

A hostname is a text string which corresponds to an IP address. It is also expressed in "dot notation", with each segment of the address identifying a progressively wider scope.

==> An example of a hostname is "acad1.alaska.edu".

This name corresponds to an IP address of 137.229.150.16 and indicates a machine named "acad1" at a university server called alaska in the educational domain.

E-mail Address

An e-mail address is a lot like the mailing address you use for US mail. It usually consists of the following parts:

{login name}@{hostname}

The {login name} corresponds to a PID for mail sent to the University of Alaska, ACAD1 mail server. The {hostname} indicates the particular machine which will receive mail for your login name (see the hostname section above). These two parts are joined by a "@" symbol. You can read an e-mail address as "login name at hostname", e.g.:

mail sent to: tnelc@acad1.alaska.edu

can be read as "mail sent to user tnelc at the machine called acad1 in the Juneau acad1 subnet of the University of Alaska in the educational domain.

Putting it all together

Using a postal analogy, the above terms can be explained more clearly.

A PID corresponds to the addressee on a letter. The host name corresponds to the address on the letter, while the IP address corresponds to the physical location of the mailbox for that address. (It could be a street mailbox, or a PO Box, it doesn't matter.) The email address corresponds to the entire envelope address, e.g. name plus address.

email your answers to: pti mailbox

The Facilitator :-)

PID, IP, Email and Host Names