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NAT Section

The

NAT (Network Address Translation)

section allows multiple users to access

the Internet sharing one public IP.

Figure 1 shows the

NAT

main screen.

FIGURE 1

NAT main screen

TABLE 1

NAT Settings

PARAMETER

DESCRIPTION

Enable

or

disable

NAT

module function

Turn on / turn off the NAT function

NAT >> ADDRESS

MAPPING

It allows one or more public IP addresses to be shared by multiple internal us-

ers. This also hides the internal network for increased privacy and security. En-

ter the

Public IP address

you wish to share into the Global IP field. Enter a

range of internal IPs that will share the global IP into “from” field.

Figure 2 represents Address configuration to share in public or global Internet.

DISCUS™ DRG A124G

Address Mapping configuration

NAT >> VIRTUAL SERVER

If you configure the Router as a virtual server, remote users accessing services

such as web or FTP at your local site via public IP addresses can be automati-

cally redirected to local servers configured with private IP addresses. In other

words, depending on the requested service (TCP / UDP port number), the Rou-

ter redirects the external service request to the appropriate server (located at

another internal IP address).

In

Figure 3, the Router configuration working as

Virtual Server

is shown.

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DISCUS™ DRG A124G

Virtual Server Router configuration

For example, if you set

Type/Public Port

to TCP/80 (http or web) and the

Private

IP/Port

to 192.168.1.40/80 then all HTTP requests from outside users will be

transferred to 192.168.1.40 on port 80. Therefore by just entering the IP ad-

dress provided by the ISP, Internet users can access the service they need at

the local address to which you redirect them.

The more common TCP service ports include:HTTP:80, FTP:21, Telnet:23 and

POP3:110.

All list of ports is maintained at the following link:

http://www.iana.org/assignments/port-numbers.

NAT >> SPECIAL

APPLICATION

Some applications do require multiple connections, such as Internet gaming,

video conferencing and Internet telephony. These applications may not work

when

Networks Address Translation (NAT)

is enabled. If you need to run ap-

plications that require multiple connections, use there screens to specify the

additional public ports to be opened for each application.

Figure 4 shows the insertion of port (Trigger port) to open the inbound traffic for

special applications.

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DISCUS™ DRG A124G

Trigger port configuration for special application inbound traffic

TABLE 2

List of fields on the Special Applications menu

PARAMETER

DESCRIPTION

Trigger Port

Allows to open the inbound traffic for special application such as Internet

gaming, video conferencing, Internet telephony and others.

Trigger Type

Select TCP or UDP protocol.

Public port

Port towards network.

Public Type

Select TCP or UDP protocol.

Enabled

Enable / Disable the Trigger port.

Popular appli-

cations

To quickly copy the entry to the table.

NAT >> NAT MAPPING

TABLE

This section displays the current

NAPT (Network Address Port Translation)

address mapping (see

Figure 5).

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DISCUS™ DRG A124G

Network Address Port Translation table

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