Ports can be divided into virtual ports and physical ports, where virtual ports refer to the ports inside the computer or in the switch router and are invisible. Such as port 80, port 2 1, port 23, etc. Physical ports, also known as interfaces, are visible ports, RJ45 network ports on the computer backplane and RJ45 ports, such as switch router hubs. Phones using RJ 1 1 jack also belong to the category of physical ports.
Extended data
By protocol type
According to the protocol type, it can be divided into TCP, UDP, IP and ICMP (Internet Control Message Protocol) ports. The following mainly introduces TCP and UDP ports:
(1)TCP port
TCP port, transmission control protocol port, needs to establish a connection between the client and the server, which can provide reliable data transmission. Common ports are 2 1 port of FTP service, 23 port of Telnet service, 25 port of SMTP service and 80 port of HTTP service.
(2)UDP port
UDP port, that is, the user datagram protocol port, does not need to establish a connection between the client and the server, so the security cannot be guaranteed. Common ones are port 53 for DNS service, port 16 1 for SNMP service, ports 8000 and 4000 used by QQ and so on.