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This is a list of TCP and UDP port numbers used by protocols for operation of network applications. The Transmission Control Protocol (TCP) and the User Datagram Protocol (UDP) only need one port for bidirectional traffic. TCP usually uses port numbers that match the services of the corresponding UDP implementations, if they exist, and vice versa.
For TCP, port number 0 is reserved and cannot be used, while for UDP, the source port is optional and a value of zero means no port. A process associates its input or output channels via an internet socket , which is a type of file descriptor , associated with a transport protocol , a network address such as an IP address , and a port number.
The communications are usually done over TCP port number 443 (or 80 in the case of unsecured connections), which is beneficial for environments that block non-web Internet connections using a firewall. Additionally, WebSocket enables streams of messages on top of TCP. TCP alone deals with streams of bytes with no inherent concept of a message.
Some examples include: FTP (20 and 21), SSH (22), TELNET (23), SMTP (25), HTTP over SSL/TLS (443), and HTTP (80). [e] Registered ports are typically used by end-user applications as ephemeral source ports when contacting servers, but they can also identify named services that have been registered by a third party. Dynamic or private ports can ...
A registered port is a network port designated for use with a certain protocol or application.. Registered port numbers are currently assigned by the Internet Assigned Numbers Authority (IANA) and were assigned by Internet Corporation for Assigned Names and Numbers (ICANN) before March 21, 2001, [1] and were assigned by the Information Sciences Institute (USC/ISI) before 1998.
This is a list of the IP protocol numbers found in the field Protocol of the IPv4 header and the Next Header field of the IPv6 header.It is an identifier for the encapsulated protocol and determines the layout of the data that immediately follows the header.
In HTTP implementations, TCP/IP connections are used using well-known ports (typically port 80 if the connection is unencrypted or port 443 if the connection is encrypted, see also List of TCP and UDP port numbers). [44] [45] In HTTP/2, a TCP/IP connection plus multiple protocol
The "Server port" column indicates the port from which the server transmits data. In the case of FTP, this port differs from the listening port. Some protocols—including FTP, FTP Secure, FASP, and Tsunami—listen on a "control port" or "command port", at which they receive commands from the client.