44

Configuring the Advanced Settings

DNS servers

DNS is a decentralised service that assigns PC names or Internet addresses (

Domain

names

) and IP addresses to one another. A DNS server has to administer this informa-

tion for each server or each LAN with an Internet connection.

Normally your Internet provider supplies you with a

DNS server

, which makes this

assignment when the connection to the Internet is set up. If necessary, you can define

the DNS server to be used for Internet connections manually.

ì

In the

Advanced Settings

–

Internet

menu, select the entry

DNS Servers

.

ì

Activate the

Use custom DNS servers

function by selecting

On

.

ì

Enter the IP addresses for your

Preferred DNS server

and

Alternate DNS server

.

ì

Click on

OK

to apply the settings.

MAC address

If you had Internet access through the same Internet provider before connecting the

Gigaset SE361 WLAN, then it is possible that the MAC address of one of your PCs was

used for registration when access was configured. In this case, you must either replace

the current MAC address with the MAC address registered with the Internet provider or

ask your Internet provider to register a new MAC address for your account.

Carry out the following steps:

ì

Connect a PC to the Gigaset SE361 WLAN and open the configuration environment.

ì

In the

Advanced Settings

–

Internet

menu, select the entry

MAC address

.

45

Configuring the Advanced Settings

ì

Select the MAC address that is to apply to the Internet connection:

–

Use default device MAC address

: You can leave this default setting if the MAC

address of the Gigaset SE361 WLAN is used to connect to the Internet.

–

Use MAC address of this PC

: Select this option if the MAC address of the cur-

rently connected PC was previously registered for connecting to the Internet or if

you have re-registered the MAC address of the PC on which you are currently

working.

–

Use custom MAC address

: Select this option if you have asked your Internet pro-

vider to register a new MAC address and this is not the MAC address of the PC on

which you are currently carrying out the configuration.

ì

Click on

OK

to apply the settings.

Firewall

The firewall functions of the Gigaset SE361 WLAN include various security functions for

your local network.

You can block individual PCs' access to individual services or Internet sites (see page 46).

The firewall functions for the Gigaset SE361 WLAN are activated and configured in the

factory. If you wish to deactivate the firewall, carry out the following steps:

ì

In the

Advanced Settings

–

Internet

menu, select the entry

Firewall

.

ì

Select the required option.

ì

Click on

OK

to apply the settings.

46

Configuring the Advanced Settings

Setting up access control to the Internet

The

Access Control

function allows you to block access to various Internet services for

one or more PCs.

Select

Access Control

in the

Advanced Settings

–

Internet

–

Firewall

menu.

ì

Activate the

Access Control

function via the option

On

.

You have the following setting option for

Access Control

:

URL filter

The URL filter allows you to block access to certain Internet sites or Internet domains, or

to limit accesses to certain Internet sites. Once you have entered the relevant URLs you

can then create access rules that apply the URL filter to the selected clients in your net-

work.

ì

In the

Advanced Settings

–

Internet

–

Firewall

menu, select

Access Control

.

ì

Select

Filtering mode

, i.e. whether you wish to allow or block access to the URLs in

the list.

ì

Enter the required URL in the field.

ì

Click on

Delete

to delete an entry. Click on

Add

to create a new entry.

ì

Click on

OK

to apply the settings.

47

Configuring the Advanced Settings

Setting up the NAT function

Your Gigaset SE361 WLAN comes provided with the NAT (Network Address Translation)

function. With address translation, several users on your local network can access the

Internet via one or more public IP addresses. In the default setting, all local IP addresses

are mapped to your router's public IP address.

One property of NAT is that data from the Internet is not allowed into your local network

unless it has been explicitly requested by one of the PCs on that network. Most Internet

applications run behind the NAT firewall without any problems. If you request Internet

pages, for example, or send and receive e-mails, the request for data from the Internet

comes from a PC on the local network and the router allows the data through. The

router opens exactly

one

port for the application. A port is an internal PC address

through which the data is exchanged between a server on the Internet and a client on

a PC in the local network. Communicating via a port follows the rules of a specific pro-

tocol (TCP or UDP).

If an external application tries to send a call to a PC within the local network, the router

will block it. There is no open port via which the data could enter the local network.

Some applications, such as games on the Internet, require several links, i.e. several ports

so that the players can communicate with each other. In addition, these applications

must also be permitted to send requests from other users on the Internet to the user on

the local network. Initially, these applications will not work if Network Address Transla-

tion (NAT) is activated.

Using port forwarding (the forwarding of requests to specific ports) you make the router

forward requests from the Internet for a certain service, e.g a game, to the appropriate

port or ports on the PC on which the game is running.

Port triggering is a specific variant of port forwarding. Unlike port forwarding, in this

case the Gigaset SE361 WLAN forwards data from the set port block to the PC which has

previously sent data to the Internet via a certain port (trigger port). This means that per-

mission for data transfer is not tied to one specific PC in your network, but only to the

port numbers of the required Internet service.

Where configuration is concerned, this means:

u

You have to define a so-called trigger port for the application and also the protocol

(TCP or UDP) that this port uses. To this trigger port you then assign the public ports

that have to be opened for the application.

u

The router checks all outgoing data for port number and protocol. If it recognises a

match of port and protocol to a defined trigger port, then it will open the assigned

public ports and notes the IP address of the PC that sent the data. If data comes back

from the Internet via one of these public ports, it allows the data through and routes

it to the right PC. A trigger event always comes from a PC within the local network.

If a trigger port is addressed from outside, it is simply ignored by the router.

48

Configuring the Advanced Settings

When the Gigaset SE361 WLAN is delivered, the

NAT

function (Network Address Trans-

lation) is activated, i.e. all IP addresses of PCs in the local network are mapped to the

router's public IP address when accessing the Internet.

You can use the NAT settings for the Gigaset SE361 WLAN to

u

set up port triggering for special applications (see page 49),

u

set up the Gigaset SE361 WLAN as a virtual server by configuring Port Forwarding

(see page 50),

u

open the firewall for selected PCs (see page 51).

You can activate or deactivate the NAT function (default setting: NAT function is acti-

vated).

ì

In the

Advanced Settings

–

Internet

menu, select

Address Translation (NAT)

and

mark the required option.

Note:

u

An application that is configured for port triggering can only be run by one user in

the local network at a time.

u

As long as the public ports are open, they can be used by unauthorised persons to

gain access to a PC in the local network.

Note:

For the functions described below you must make sure that the IP addresses of the

PCs do not change. If the IP addresses of the PCs are assigned via the DHCP server of

the Gigaset SE361 WLAN, you must select the option

Never expires

for the settings

on the

Local Network

screen for

Lease time

(see page 55) or assign static IP

addresses for the PCs.