Reference Manual for the ProSafe VPN Firewall FVS318v3
6Glossary
January 2005
IP Address
A four-byte number uniquely defining each host on the Internet, usually written in dotted-decimal notation
with periods separating th e bytes (for example, 134.177.244.57). Ranges of addresses are assi gned by
Internic, an organization formed for this purpose.
ISP
Internet service provider.
L
LAN
See “Local Area Network”
Local Area Network
A communications network serving users within a limited area, such as one floor of a building. A LAN
typically connects multiple personal computers and shared network devices such as storage and printers.
Although many technologies exist to implement a LAN, Ethernet is the most common for connecting
personal computers and is limited to a distance of 1,500 feet. LANs can be connected together, but if
modems and telephones connect two or more LANs, the larger network constitutes what is called a WAN or
Wide Area Network.
M
MAC
(1) Medium Access Control. In LANs, the sublayer of the data link control layer that supports
medium-dependent functions and uses the services of the physical layer to provide services to the logical
link control (LLC) sublayer. The MAC sublayer includes the method of determining when a device has
access to the transmission medium. (2) Message Authentication Code. In computer security, a value that is a
part of a message or accompanies a message and is used to determine that the contents, origin, author, or
other attributes of all or part of the message are as they appear to be. (IBM Glossary of Computing Terms)
MAC address
The Media Access Control address is a unique 48-bit hardware address assigned to every network interface
card. Usually written in the form 01:23:45:67:89:ab.
Maximum Receive Unit
The size in bytes of the largest packet that can be sent or received.
Maximum Transmit Unit
The size in bytes of the largest packet that can be sent or received.