Netgear R4500 – N900 Wireless Dual Band Gigabit Router Manual Do Utilizador

Verify connectivity across the LANs. 

A computer on that joins the network can connect to the Internet or share files and 
printers with computers and servers connected to the other access point.

Port Forwarding and Port 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 the router does not 
recognize their replies.

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:

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

browser session. 

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.

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 

information and then modifies the source information in the request message, performing 

Network Address Translation (NAT):