Port Numbers In Computer Networks

A port is an endpoint of communication in an operating system. While the term is also used for female connectors on hardware devices, in software it is a logical construct that identifies a specific process or a type of network service.

When referring to a network or to the Internet, a software or network port is a location where information is sent. For example, port 80 is the HTTP network port. A listing of commonly known and used ports can also be found on the below listing.

• 18 – MSP (Message Send Protocol)
• 20 - FTP (File Transfer Protocol) for data transfer
• 21 – FTP (File Transfer Protocol) for data control
• 23 – Telnet
• 22 – SSH - Remote Login Protocol
• 25 - SMTP (Simple Mail Transfer Protocol) for is used for sending mails.
• 53 – DNS (Domain Name System)
• 67 – DHCP (Dynamic Host Configuration Protocol) for sending data to the server – Bootps
• 68 – DHCP (Dynamic Host Configuration Protocol) for data to the client - Bootpc
• 80 – HTTP (Hypertext Transfer Protocol)
• 109 – POP2
• 110 - POP3 (Post Office Protocol) used for receiving mails but it uses log-in process.
• 119 – NNTP (Network News Transfer Protocol)
• 137 – NetBIOS Name Service
• 139 – NetBIOS Datagram Service
• 143 – IMAP4 (Interim Mail Access Protocol) used for receiving mails.
• 150 – NetBIOS Session Service
• 161 – SNMP
• 179 – BGP (Border Gateway Protocol)
• 389 – LDAP (Lightweight Directory Access Protocol)
• 443 – HTTPS (HTTP-secure)
• 546 – DHCP Client
• 547 – DHCP Server