FRITZ WLAN-7390 Router Manual PDF (Setup & Configuration Guide)

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Glossary

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IP address

In IP-based networks, for instance in the Internet and local

networks, all connected devices are addressed via their IP

addresses. So that data packets are sure to be delivered

to the right address, each IP address may be assigned on-

ly once within the Internet or a local IP network.

The IP address consists of four three-digit groups of num-

bers (for instance, 192.168.178.247). Each group of num-

bers can assume values between 000 and 255.

Every IP address contains two components: the network

address and the host address. These two components can

be read out of an IP address only if the subnet mask is al-

so specified.

IP addresses can be public or private, and also fixed or as-

signed dynamically. See the corresponding entries in the

Glossary for more information.

IP addressing

Addressing is one of the main functions of the Internet

Protocol (IP). Internet addresses can be written in deci-

mal, octal or hexadecimal notation. The FRITZ!Box uses

“dotted-decimal” notation: The four bytes of an address

are represented by decimal numbers separated by dots.

The total volume of Internet addresses, the address

space, is separated into classes (A, B, C, D, and E). The full

set of IP addresses, called the address space, is grouped

into address classes designated as A, B, C, D and E. Only

the first three of these five address classes are actually

used. These classes can be described as follows:

Classes

Properties

Network Address

Decimal Value

Class A

address

few networks, many hubs

0-127

Class B

address

intermediate distribution of

networks and hubs

128-191

Class C

address

many networks, few hubs

192-223

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Glossary

Properties of IP Address Classes

Every IP address consists of two parts: the network ad-

dress and the host address. The sizes of the network ad-

dress and the host address are variable, and determined

by the first four bits (of the first byte) of the IP address.

IP

masquerading

By means of IP masquerading a computer or LAN can be

protected from unauthorized connection requests from

the Internet. Masquerading works by converting the IP ad-

dresses used in a network to one public IP address. From

the outside it appears that all requests are sent from a sin-

gle computer.

IP network

A network in which data exchange takes place on the ba-

sis of the Internet Protocol is called an IP network.

NAS

functionality

NAS is the abbreviation for Network Attached Storage

NAS designates one or more devices that are integrated

into a network to provide storage space.

In connection with the FRITZ!Box, NAS functionality means

that various services for connected USB memory are avail-

able in the FRITZ!Box so that it easier for you to use your

data and make them available in the local network. It is

easy to exchange documents in the local network via the

storage medium on the FRITZ!Box. The Media Server

makes music, pictures and videos in the network avail-

able to compatible playback devices. Files can also be re-

leased for sharing in the Internet, and local memory ex-

panded by adding online storage.

NAT

abbreviation for Network Address Translation

NAT is a process used in routers to replace the address in-

formation in data packets with new address information. A

typical application for NAT is routers that connect local

networks with the Internet. In local networks, every net-

work device has a private IP address, while generally there

is only one public IP address available for the Internet. To

grant the network devices access to the Internet, the rout-

er replaces the private IP address of the sender with its

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Glossary

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own public IP address in all outgoing data packets. The

router saves all necessary information in a table so that in-

coming data packets can then be assigned to the correct

network device.

Outside dialing

prefix

The outside dialing prefix is the digit dialed at an exten-

sion line to obtain an outside line. Generally this is “0”.

Public IP

address

A public IP address is an IP address valid in the Internet.

Every computer or router participating in the Internet must

have a uniquely assigned public IP address. This address

is usually negotiated dynamically with the Internet Service

Provider when a connection to the Internet is dialed. The

Internet Service Provider assigns the negotiated IP ad-

dress to the computer or router for the duration of an Inter-

net session.

Port

So that a single network connection on a computer can be

used by multiple applications to exchange data with re-

mote sites at the same time, a computer administers what

are known as ports for the IP-based protocols TCP and

UDP. Ports substantiate the point of access for the data

packets delivered via the IP Internet protocol. While the IP

address determines the destination computer quite gen-

erally, the port addresses the communication interface

provided by an application for a certain communication

procedure.

The Internet protocol allots 16 bits for the specification of

the port number. Thus a total of 65,535 different port

numbers can be specified. Ports up to port number 1,024

are reserved for special system applications and typical

Internet applications. These include, for instance, the port

numbers 21 for FTP (File Transfer Protocol), 25 for SMTP

(Simple Mail Transfer Protocol), 53 for DNS (Domain Name

Service) and 80 for HTTP (Hypertext Transfer Protocol).

Ports are primarily of interest to users for their role in pro-

tecting an Internet connection from external attacks. Most

firewalls offer the possibility of preventing data traffic on

certain ports. This means that certain port numbers can

be blocked to prevent data from being delivered to system

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Glossary

services. This is also a way of preventing any Trojans that

may have infected your computer from receiving data on

ports it created as means of accessing your computer for

potentially damaging activities. A firewall blocks most of

the atypical port numbers not required for normal opera-

tion of an application and offers specialized users the op-

portunity to forward specified ports.

Port forwarding

With port forwarding it is possible to specify ports that will

allow all incoming or outgoing data packets to pass

through a router or firewall.

If a computer from the local network offers server services,

for instance, the settings of a router using NAT or IP mas-

querading must enable or forward the port used by the

server service for access to incoming data packets and

thus keep it open permanently. The private IP address of

the given computer must be saved as the destination ad-

dress for all of the packets arriving at the port.

Typical server applications that require port forwarding

are FTP and Web servers. To allow access to a computer via

remote management software like Symantec pcAnywhere

or Microsoft’s Remote Desktop, or even use of a file-shar-

ing program like eMule, the required ports must be re-

leased for port forwarding. Port forwarding settings for the

most important application cases are quite simple as long

as the settings of the router or the firewall already contain

rules with a corresponding preconfiguration.

Private IP

address

Private IP addresses are used for computers and other

network devices within local IP networks.

Since many local IP networks are not connected to the In-

ternet except via single computers or routers (gateway),

certain address ranges are excluded from the publicly

available IP addresses so that they are available for as-

signment in local IP networks. An IP address may only be

assigned once within the local network. A private IP ad-

dress may exist in any number of other local networks.

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185

Stick & Surf

Stick & Surf is a technique developed by AVM for the fast,

simple, error-free and secure configuration of radio net-

works. This technique allows for the straightforward trans-

mission of all important parameters of a radio network

from the access point to any computer that is to be added

to the radio cell.

In this process the radio parameters used, including the

WLAN channel, SSID and WLAN standard used, as well as

security parameters like the encryption method and net-

work key, are transferred almost fully automatically from

the WLAN access point to the computer with the WLAN cli-

ent that is to be connected.

Subnetwork

A local IP network can consist of one subnetwork or be di-

vided into multiple subnetworks. The division into subnet-

works is performed when the local IP network is config-

ured. The subnetworks of a local IP network are also IP

networks.

Subnet mask

The subnet mask indicates which part of an IP address is

the network address and which the address of the com-

puter. The network address defines what is called the sub-

net.

Example 1

IP address

192.168.178.247

Subnet mask:

255.255.255.0

The assignment of the first three groups of numerals in the

subnet mask indicates that the first three groups of numerals in

the IP address define the network. The following addresses

result:

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