
Glossary
IP Address - A unique number used to identify device or host computers on the Internet.
Subnet Mask - The net mask used to manage sub-segments of the network.
Once a packet has arrived at an organization's gateway or connection point with its unique network
number, it can be routed within the organization's internal gateways using the subnet number as well.
The router knows which bits to look at (and which not to look at) by looking at a subnet mask. A mask
is simply a screen of numbers that tells you which numbers to look at underneath. In a binary mask, a
"1" over a number says "Look at the number underneath"; a "0" says "Don't look." Using a mask
saves the router having to handle the entire 32 bit address; it can simply look at the bits selected by
the mask, ie; 255.255.255.0.
SMTP – Simple Mail Transfer Protocol. This is the communication protocol used to send e-mail on
the Internet.
Default Gateway IP Address - A gateway is a network point that acts as an entrance to another
network. On the Internet, a node or stopping point can be either a gateway node or a host (end-point)
node. IP address is the number used to identify it.
E-Mail Address - E-mail (electronic mail) is the exchange of computer-stored messages by
telecommunication. The "address" means the unique location of an e-mail user.
Domain Name System (DNS) – A unique name used to identify an Internet site. Domain names
consist of two or more parts, separated by dots. The domain name system (DNS) is the way that
Internet domain names are located and translated into Internet Protocol addresses. A domain name
is a meaningful and easy-to-remember "handle" for an Internet address.
POP 3 - A point-of-presence (POP aka Post Office Protocol) is an access point to the Internet. A
POP necessarily has a unique Internet Protocol (IP) address. POP3 (Post Office Protocol 3) is the
most recent version of a standard protocol for receiving e-mail. POP3 is a client/server protocol in
which e-mail is received and held for you by your Internet server. Periodically, you (or your client e-
mail receiver) checks your mail-box on the server and downloads any mail.
TCP/IP - Transmission Control Protocol/Internet Protocol. TCP/IP is a set of protocols used to
connect to the Internet and Wide-Area Networks.
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