This page describes well known port numbers defined in RFC 1700.It mentions Port numbers for FTP, TELNET, HTTP, SMTP, POP3, IMAP, BIOS, SSH, DHCP used in TCP, UDP and IP protocols.

Port Numbers: The end point of a logical connection is known as port. It is a 16 bit size number ranging from 0 to 65536. The port numbers from 0 to 1024 are known as well known ports and are used for specialized services or privileged services. For example as mentioned in the table below port 80 is used for HTTP while ftp port number is 21 etc.

Table of Port numbers used for FTP, TELNET, HTTP, SMTP, POP3, IMAP, BIOS, SSH, DHCP protocols

Port numbers are pre-assigned by IANA (Internet Assigned Numbers Authority). They are specified in RFC 1700. Following table mentions port numbers for FTP, TELNET, HTTP, SMTP, POP3, IMAP, BIOS, SSH, DHCP protocols. These protocols are used in TCP or UDP connections in computer networks.

Port Number Protocol description
20, 21 port number 20 is used for FTP data while port number 21 is used for FTP Control
23 Used for TELNET
80, 8080 HTTP
161 SMTP (Simple Mail Transfer Protocol)
110 POP3
143 IMAP i.e. Interim Mail Access Protocol
137, 138, 139 port number 137 is used for BIOS Name service, 138 for NetBIOS-dgm, 139 for NetBIOS Datagram service
22 Used for SSH remote login protocol, SSH is short form of Secure Shell
67, 68 The port number 68 is used for DHCP client and 67 is used for DHCP server
53 DNS (Domain Name System)
69 TFTP (Trivial File Transfer Protocol)
70 Gopher services
79 Finger
161 SNMP
179 BGP (Border Gateway Protocol)
389 LDAP (Lightweight Directory Access Protocol)
5800, 5900 VNC

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