Multitech RouteFinder RF820 User Manual page 90

Glossary
IP Addresses
A computer on the Internet is identified by an IP Address. A computer's IP address is like a telephone number. It
identifies one address or in this case one computing device. Every computer or device on the network must have
a different IP address. An IP address consists of four groups of numbers called octets, which are separated by
periods. For example, 213 .0.0.1 is an IP address. An IP address consists of a network portion and a host
portion. The network portion identifies the subnet that the computer belongs to. The host portion identifies the
particular computer or node on that network.
IP addresses can either be dynamic (temporary) or static (permanent or fixed). A dynamic IP address is a
temporary IP address that is assigned to you by a server (usually a DHCP server) when the computer is powered
on. A static IP address is a permanent IP address that is set up on each individual computer. When your
RouteFinder dials-up your ISP, your ISP can give it a fixed or dynamic IP address. Likewise, when you power on
your computer, the RouteFinder can give your computer a dynamic or fixed IP address.
ISDN TA
(Integrated Services Digital Network Terminal Adapter) ISDN is a high speed digital telephone connection
involving the digitization of the telephone network using existing wiring. An ISDN Terminal Adapter can be thought
of as an ISDN Modem.
ISP (Internet Service Provider)
An organization that provides Internet services. An ISP is the company that provides the connection from your
computer to the Internet. An ISP can offer a range of services, such as dial-up accounts, e-mail, web hosting or
News.
L
LAN (Local Area Network)
A data network intended to serve an area of only a few square kilometers or less. This often means a small
private network in companies.
M
ML-PPP (Also called MP or MPPP)
Stands for Multilink Point to Point Protocol and is an advancement of the PPP protocol that allows for the bridging
or bundling of two ISDN or analog channels for faster connections.
MAC Address
The hardware address of a Device connected to a shared media. To find out the MAC address of your computer,
please see Troubleshooting.
N
NAT Technology
NAT is short for Network Address Translation. NAT is an Internet standard that enables a local-area network to
use one set of IP addresses for internal traffic and a second set of IP addresses for external traffic. The RF500S
provides the necessary IP address translations. NAT is sometimes referred to as "IP Address Masquerading".
This technology provides a type of firewall by hiding the internal IP addresses.
How does it work?
Every IP address on the Internet is a Registered or legal IP address. Therefore, no two IP addresses on the
Internet are the same. For you to use your network device to access the Internet you need a registered IP
address from your ISP (Internet Service Provider). Using a registered IP address on your Intranet or LAN is not
necessary. When clients on your network start surfing the Internet, your RouteFinder will receive all the requests
for information. The RouteFinder will dial-up your ISP and your ISP will give your RouteFinder a registered legal
IP address. Your RouteFinder uses this IP address to request information saying, "send all information back to me
at this IP address". In essence it appears as though all your clients requests are coming from that one IP address
(hence the name IP masquerading). When all the information comes back through the RouteFinder, it sorts the
data using an Address Translation Table and returns the data to the computer on your network that requested it.
If someone on the Internet tries to access your network, the firewall function of the RouteFinder stops the request.
The device will not reverse translate network addresses unless you have specifically allowed this feature using
the Virtual Server function (IP Mapping).
Multi-Tech Systems, Inc. RouteFinder SOHO RF820/RF820-AP & RF830/RF830-AP User Guide (S000399E) 90