Internet Protocol Suite is the conceptual model and set of communications protocols used on the Internet and similar computer networks. It is commonly known as TCP/IP because the original protocols in the suite are the Transmission Control Protocol (TCP) and the Internet Protocol (IP).1
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The Internet Engineering Task Force (IETF) is a large open international community of network designers, operators, vendors, and researchers concerned with the evolution of the Internet architecture and the smooth operation of the Internet. It is open to any interested individual. The IETF Mission Statement is documented in RFC 3935.2
A Request for Comments (RFC) is a type of publication from the Internet Engineering Task Force (IETF) and the Internet Society (ISOC), the principal technical development and standards-setting bodies for the Internet.
An RFC is authored by engineers and computer scientists in the form of a memorandum describing methods, behaviors, research, or innovations applicable to the working of the Internet and Internet-connected systems. It is submitted either for peer review or simply to convey new concepts, information, or (occasionally) engineering humor. The IETF adopts some of the proposals published as RFCs as Internet Standards.
Request for Comments documents were invented by Steve Crocker in 1969 to help record unofficial notes on the development of ARPANET. RFCs have since become official documents of Internet specifications, communications protocols, procedures, and events.3
In the internet protocol suite, a port is an endpoint of communication in an operating system. While the term is also used for female connectors on hardware devices (see computer port), in software it is a logical construct that identifies a specific process or a type of network service.
A port is always associated with an IP address of a host and the protocol type of the communication, and thus completes the destination or origination network address of a communication session. A port is identified for each address and protocol by a 16-bit number, commonly known as the port number. For example, an address may be "protocol: TCP, IP address: 126.96.36.199, port number: 80", which may be written 188.8.131.52:80 when the protocol is known from context.4
Transport layer protocols, such as the Transmission Control Protocol (TCP) and the User Datagram Protocol (UDP), specify a source and destination port number in their headers. A port number is a 16-bit unsigned integer, thus ranging from 0 to 65535.a A process associates its input or output channels, via an Internet socket (a type of file descriptor), with a transport protocol, a port number, and an IP address. This process is known as binding, and enables sending and receiving data via the network. The operating system's networking software has the task of transmitting outgoing data from all application ports onto the network, and forwarding arriving network packets to processes by matching the packet's IP address and port number. Only one process may bind to a specific IP address and port combination using the same transport protocol. Common application failures, sometimes called port conflicts, occur when multiple programs attempt to bind to the same port numbers on the same IP address using the same protocol.5
|20||File Transfer Protocol (FTP)|
|21||File Transfer Protocol (FTP)|
|22||Secure Shell (SSH)|
|25||Simple Mail Transfer Protocol (SMTP)|
|53||Domain Name System (DNS)|
|80||Hypertext Transfer Protocol (HTTP)|
|110||Post Office Protocol, version 3 (POP3)|
|143||Internet Message Access Protocol (IMAP)|
|161||Simple Network Management Protocol (SNMP)|
|179||Border Gateway Protocol (BGP)|
|389||Lightweight Directory Access Protocol (LDAP)|
|443||Hypertext Transfer Protocol (HTTP) over TLS/SSL (HTTPS)|
|1293||Internet Protocol Security (IPSec)|
|1723||Point-to-Point Tunneling Protocol (PPTP)|