Chapter

10

NAT Forwarding

Router’s NAT (Network Address Translation) feature makes the devices in the LAN use

the same public IP address to communicate in the Internet, which protect the local

network by hiding IP addresses of the devices. However, it also brings about the

problem that external host cannot initiatively communicate with the specified device

in the local network.

With forwarding feature the router can penetrate the isolation of NAT and allows the

external hosts in the Internet to initiatively communicate with the devices in the local

network, thus to realize some special functions.

TP-LINK router includes four forwarding rules. If two or more rules are set, the priority

of implementation from high to low is Virtual Servers, Port Triggering, UPNP and DMZ.

This chapter contains the following sections:

•

Share Local Resources in the Internet by Virtual Server

•

Open Ports Dynamically by Port Triggering

•

Make Applications Free from Port Restriction by DMZ

•

Make Xbox Online Games Run Smoothly by UPnP

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10. 1.

Share Local Resources in the Internet by Virtual

Server

When you build up a server in the local network and want to share it on the Internet,

Virtual Server can realize the service and provide it to the Internet users. At the same

time virtual server can keep the local network safe as other services are still invisible

from the Internet.

Virtual server can be used for setting up public services in your local network, such as

HTTP, FTP, DNS, POP3/SMTP and Telnet. Different service uses different service port.

Port 80 is used in HTTP service, port 21 in FTP service, port 25 in SMTP service and port

110 in POP3 service. Please verify the service port number before the configuration

.

Share my personal website I’ve built in local network with my

friends through the Internet.

For example,

the personal website has been built in my home

PC (192.168.0.100). I hope that my friends in the Internet can

visit my website in some way. The PC is connected to the router

with the WAN IP address 218.18.232.154.

Router

WAN: 218.18.232.154

LAN

Home

Personal Website

1.

Assign a static IP address to your PC, for example

192.168.0.100.

2.

Visit

http://tplinkwifi.net

, and log in with the username and

password you‘ve set for the router.

3.

Go to

Advanced

>

NAT Forwarding

>

Virtual Servers

.

4.

Click

Add

. Click

View Existing Services

and select

HTTP

. The

external port, internal port and protocol will be automatically

filled with contents. Enter the PC’s IP address 192.168.0.100

in the

Internal

IP

field.

5.

Click

OK

to save the settings.

I want to:

How can I

do that?

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Chapter 10

NAT Forwarding

Tips:

3.

It is recommended to keep the default settings of

Internal Port

and

Protocol

if you

are not clear about which port and protocol to use.

4. If the service you want to use is not in the

Service

Type

, you can enter the

corresponding parameters manually. You should verify the port number that the

service needs.

5. You can add multiple virtual server rules if you want to provide several services in

a router. Please note that the

External

Port

should not be overlapped.

Users in the Internet can enter

http:// WAN IP

(in this example:

http:// 218.18.232.154) to visit your personal website.

Tips:

1. WAN IP should be a public IP address. For the WAN IP is assigned dynamically by

ISP, it is recommended to apply and register a domain name for the WAN refer to

12. 4. Set Up a Dynamic DNS Service Account

. Then you can use

http:// domain name

to visit the website.

2. If you have changed the default

External Port

, you should use

http:// WAN IP:

External Port

or

http:// domain name: External Port

to visit the website.

10. 2.

Open Ports Dynamically by Port Triggering

Port triggering can specify a triggering port and its corresponding external ports.

When a host in the local network initiates a connection to the triggering port, all the

external ports will be opened for subsequent connections. The router can record the IP

address of the host. When the data from the Internet return to the external ports, the

router can forward them to the corresponding host. Port triggering is mainly applied

to online games, VoIPs and video players. Common applications include MSN Gaming

Zone, Dialpad and Quick Time 4 players, etc.

Follow the steps below to configure the port triggering rules:

Done!

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Chapter 10

NAT Forwarding

1. Visit

http://tplinkwifi.net

, and log in with the username and password you’ve set for

the router.

2. Go to

Advanced

>

NAT Forwarding

>

Port Triggering

and click

Add

.

3. Click

View Existing Applications

, and select the desired application. The external port,

internal port and protocol will be automatically filled with contents. The following

picture takes application

MSN Gaming Zone

as an example.

4. Click

OK

to save the settings.

Tips:

1. You can add multiple port triggering rules according to your network need.

2. The triggering ports can not be overlapped.

3. If the application you need is not listed in the Existing Applications list, please enter the parameters manually.

You should verify the external ports the application uses first and enter them into External Port field according

to the format the page displays.

10. 3.

Make Applications Free from Port Restriction by

DMZ

When a PC is set to be a DMZ (Demilitarized Zone) host in the local network, it is totally

exposed to the Internet, which can realize the unlimited bidirectional communication

between internal hosts and external hosts. The DMZ host becomes a virtual server with

all ports opened. When you are not clear about which ports to open in some special

applications, such as IP camera and database software, you can set the PC to be a DMZ

host.

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Chapter 10

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Note:

DMZ is more applicable in the situation that users are not clear about which ports to open. When it is enabled, the

DMZ host is totally exposed to the Internet, which may bring some potential safety hazard. If DMZ is not in use,

please disable it in time.

Make the home PC join the Internet online game without port

restriction.

For example,

due to some port restriction, when playing the

online games, you can login normally but cannot join a team

with other players. To solve this problem, set your PC as a DMZ

with all ports opened.

1.

Assign a static IP address to your PC, for example

192.168.0.100.

2.

Visit

http://tplinkwifi.net

, and log in with the username and

password you’ve set for the router.

3.

Go to

Advanced

>

NAT Forwarding

>

DMZ

and select the

checkbox to enable DMZ.

4.

Enter the IP address 192.168.0.100 in the

DMZ Host IP

Address

filed.

5.

Click

Save

to save the settings.

The configuration is completed. You’ve set your PC to a DMZ

host and now you can make a team to game with other players.

10. 4.

Make Xbox Online Games Run Smoothly by UPnP

UPnP (Universal Plug and Play) protocol allows the applications or host devices

to automatically find the front-end NAT device and send request to it to open the

corresponding ports. With UPnP enabled, the applications or host devices in the

both sides of NAT device can freely communicate with each other realizing the

seamless connection of the network. You may need to enable the UPnP if you want

to use applications for multiplayer gaming, peer-to-peer connections, real-time

communication (such as VoIP or telephone conference) or remote assistance, etc.

I want to:

How can I

do that?

Done!