Port forwarding and triggering, Remote computer access basics – NETGEAR N600 Wireless Dual Band Router WNDR3400v2 User Manual

Page 82

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Advanced Settings

82

N600 Wireless Dual Band Router WNDR3400v2

4.

Click Apply to save your changes.

5.

Verify connectivity across the LANs.

A computer on any wireless or wired LAN segment of the router should be able to
connect to the Internet or share files and printers with any other wireless or wired
computer or server connected to the other access point.

Port Forwarding and Triggering

By default, the router blocks inbound traffic from the Internet to your computers except replies
to your outbound traffic. You might need to create exceptions to this rule for these purposes:

To allow remote computers on the Internet to access a server on your local network.

To allow certain applications and games to work correctly when their replies are not

recognized by your router.

Your router provides two features for creating these exceptions: port forwarding and port
triggering. The next sections provide background information to help you understand how
port forwarding and port triggering work, and the differences between the two.

Remote Computer Access Basics

When a computer on your network needs to access a computer on the Internet, your
computer sends your router a message containing the source and destination address and
process information. Before forwarding your message to the remote computer, your router
has to modify the source information and create and track the communication session so that
replies can be routed back to your computer.

Here is an example of normal outbound traffic and the resulting inbound responses:

1.

You open a browser, and your operating system assigns port number 5678 to this

browser session.

2.

You type http://www.example.com into the URL field, and your computer creates a web page

request message with the following address and port information. The request message is

sent to your router.

Source address. Your computer’s IP address.

Source port number. 5678, which is the browser session.

Destination address. The IP address of www.example.com, which your computer finds
by asking a DNS server.

Destination port number. 80, which is the standard port number for a web server
process.

3.

Your router creates an entry in its internal session table describing this communication

session between your computer and the web server at www.example.com. Before sending

the web page request message to www.example.com, your router stores the original

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