Shulou(Shulou.com)06/01 Report--

one。 Overview:

In network technology, Port includes two types: logical port and physical port. Physical ports refer to physically existing ports, such as hubs, switches, and interfaces used on routers to connect other network devices, such as RJ-45 ports. Logical port refers to the port used to differentiate services logically, such as the service port in TCP/IP protocol. The port number is identified by 16 bits, so the port number ranges from 0 to 65535, such as port 80 for browsing web services, port 21 for FTP services, and so on. Because of the large number of physical and logical ports, each port is numbered in order to distinguish the ports, which is the port number.

two。 Port number classification:

(1)。 Familiar with port numbers: values range from 0 to 1024, and IANA assigns these port numbers to some of the most important applications in TCP/IP so that all users can know them. (usually bound on the server. )

(2)。 Registered port number: the value is between 1024 and 49151, which is used by applications that are not familiar with port numbers. The use of such port numbers must be registered at IANA in accordance with the prescribed procedures to prevent duplication. 49151 is 3/4 of 65535. (generally used on the server)

(3)。 Short-term port number: the value is between 49152 and 65535, which is dynamically selected when the client program is running. when the communication ends, the port number just used will be recycled by the system for use by other client processes. (used on the client side)

PS: for more information, please refer to Xie Xiren, 6th edition of computer Network, page 192.

The IANA port number query address is as follows:

Http://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xml

three。 Common port number:

TCP port 21: FTP file transfer service

TCP 23 port: TELNET terminal emulation service

TCP port 25: SMTP simple mail transfer service

UDP port 53: DNS domain name resolution service

TCP port 80: HTTP hypertext transfer service

TCP 110port: the port used by POP3 Post Office Protocol version 3

TCP port 443: HTTPS encrypted hypertext transfer service

TCP 1521 port: Oracle database service

TCP 1863 port: the port used by MSN Messenger's file transfer function

TCP 3389 port: the port used by Microsoft RDP Microsoft remote Desktop

TCP 5631 port: the port used by Symantec pcAnywhere to remotely control data transmission

UDP 5632 port: the port used by the Symantec pcAnywhere master terminal when scanning the controlled terminal

TCP 5000 port: the port used by MS SQL Server

UDP 8000 port: Tencent QQ

four。 Summary:

On the network, an IP address plus a port number determines the only process on the network, and the port number between 0x1024 binds commonly used programs / processes. Before the client wants to communicate with the server, the operating system binds a short port number to the client socket, and when the link is released, the port number is recycled by the system for use by other links. (be sure to remember my common port number marked with blue)

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