What is Port Triggering used for?

In this tutorial, we are going to see What is Port Triggering used for?

First of all, we recommend you to see What is NAT (Network Address Translation)?.
 

 
 

What is Port Triggering used for?

Most client-server applications make a request to a remote host on a given port and open a return port to get the data. However, some applications use more than one port to exchange data with the server. For example, FTP, where a connection is established on port 21, but the data is transferred on port 20. Thus, with the NAT mechanism, after a connection request on port 21 of a remote FTP server, the gateway expects a connection on a single port and will refuse the connection request on port 20 of the client.

There is a mechanism derived from NAT, called Port Triggering, which allows connection to some ports (port forwarding) if a condition (request) is met. This is conditional port forwarding, which means that a port is not left open all the time, but only when an application needs it.

 
Computer Network MCQ – Questions and Answers – Part 1Networking MCQs questions with answers to prepare for exams, tests, and certifications. These questions are taken from a real written exam and some parts are…Read More