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Table of contents
1. The concept of network port
2. Classification of network ports
3. The role of the network port
foreword
This article will talk about the concept, classification, function and common port numbers of network port numbers in the future.
1. The concept of network port
Ports can be divided into virtual ports and physical ports.
A virtual port refers to a port inside a computer or inside a switch router , which is not visible. Such as port 80, port 23 and so on.
A physical port refers to an interface connected to other network devices and is a visible interface. Interfaces on devices such as ADSL Modem, hubs, switches, and routers.
2. Classification of network ports
1. Recognized ports
The range is 0~1023, usually the communication of these ports clearly shows the agreement of some kind of service.
2. Register port
The range is 1024-49151, there are many services bound to these ports, and these ports are used for many other purposes as well.
3. Dynamic and private ports
The range is 49152~65535, theoretically, these ports should not be allocated for services. In fact, machines are usually assigned dynamic ports from 1024 onwards. But there are exceptions: SUN's RPC port starts from 32768.
3. The role of the network port
In network communication, ports can help identify and distinguish different applications or services . For example, a web server uses port 80 to provide HTTP services, and an SMTP server uses port 25 to provide mail services. Ports enable network communications by enabling network devices and applications to determine the destination and source of communication data.
4. Common port numbers
1. Port number: 21
FTP: File Transfer Protocol, used for upload and download.
2. Port number: 22
SSH: Secure Shell Protocol, a security protocol for network or remote login sessions, etc.
3. Port number: 23
Telnet: Remote login protocol, which is a commonly used method for remotely controlling web servers.
4. Port number: 25
SMTP: Simple mail transfer protocol, which can specify the recipient's server.
5. Port number: 80
HTTP: Hypertext Transfer Protocol, used more in early web pages, but due to security issues, it has now been eliminated.
6. Port number: 443
HTTPS: Hypertext Transfer Security Protocol, because of the use of certificates, the security is better, and it is now mainstream on web pages.
7. Port number: 69
TFTP: Trivial File Transfer Protocol for simple/inexpensive file transfers.
8. Port number: 110
POP3: Mail protocol, which simplifies user operations, does not need to participate in the process of reading mail, and can be processed offline.
9. Port number: 161
SNMP: Simple Network Management Protocol
10. Port number: 3389
Windows Remote Desktop: In many environments, remote springboard and port mapping need to be known