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Glossary
162 Glossary User’s Manual
PAT
Port Address Translation allows you to redirect internal or external data traveling
via ports to specific locations. For instance you want everyone using Internet
newsgroups (port 113) to be redirected to your internal news-server. All external
web requests (typically on port 80) could also be directed to your web server
inside your company. This redirection can also be to different ports. To redirect
IP addresses you would use NAT.
See the technology overview section on PAT for a more detailed explanation on
what it can do for you.
Ping
The Packet Internet Groper is a software utility used to verify if a remote device is
accessible over a network. After the remote device is identified by either its IP
address or its domain name the program or utility will send a small data packet to
that device and wait to hear a reply. This reply uses the ICMP Echo function and
will also usually include a time stamp identifying how long the packet exchange
took.
Port
While people are getting more familiar with the IP addresses used on the Internet
few people realize that for each different address there are over 65,000 channels
over which the data can travel. Fortunately most communication takes place over
preset channels (such as channel 80 for reaching for a web page.)
Some software makes use of random channels so if you want to filter data by the
port address it is important that you know which ports are being used by which
software on your network.
Port Scan
A network attack where the attacker tries to gain information about software
running on servers or workstations. The attacker attempts to make access with
every available TCP port on a computer and by analyzing the result the attacker
can then focus their attack on the specific software.
PPP
The Point-to-Point Protocol provides a standard method for transporting IP data
packets over point-to-point links (such as a link from a home computer to the
Internet via an Internet Service Provider). This simple link between two network
devices allows data packet transport between the two devices in full-duplex
simultaneous bidirectional operation.
See RFC1661.