What is Port number?

A Port number is a part of addressing information. It identifies a specific process or other network message is to be forwarded when it arrives at a server. It can identify a network-based application uniquely on a server. It allows different applications to share the network resources simultaneously on the same computer. They are associated with TCP/IP network connections which can be used to identify the message senders and receivers. This article guides to check Port 80 connections in a server with SSH command.

Some Common Port numbers are as follows:

20    –  FTP data

21     –  FTP Control

22    –  SSH remote Login Protocol

110   –  POP3

143  –  IMAP

443  –  HTTPS

156   –  SQL Server

1433 – MsSQL

3306 – MySQL

Command to check port 80 connections via SSH:

Generally, the ‘netstat’ command is used to check the number of connections on the machine. This command displays the services listening to the ports and also the details of current connections on a Linux server. The below command is used to check the port 80 connection via SSH.

netstat -anp |grep :80 |wc -l