Port: 0 Service: Reserved
Description: Usually used to analyze the operating system. When you try to connect it to a port that is usually closed, it will produce different results. A typical scan uses the IP address 0.0.0.0, sets the ACK bit and broadcasts it in the Ethernet layer.
Port: 1 Service: tcpmux
Description: This means that someone is looking for SGIIrix machine. Irix is the main provider of tcpmux, which is turned on by default in this system.
Port: 7 Service: Echo
Description: When searching for Fraggle amplifier, you can see many messages sent by people to X.X.X.0 and X.X.X.255.
Port: 19 Service: Character Generator
Description: This is a service that only sends characters. The UDP version will respond to packets containing junk characters after receiving UDP packets. When TCP connects, it sends a data stream containing junk characters until the connection is closed.
Port: 2 1 service: FTP
Description: FTP server opens ports for uploading and downloading. The most common attacker is to find a way to open anonymous's FTP server. These servers have read-write directories.
Port: 22 Service: Ssh
Description: The connection between TCP established by PcAnywhere and this port may be to find ssh. This service has many weaknesses. If configured in a specific mode, many versions that use the RSAREF library will have many loopholes.
Port: 23 Service: Telnet
Description: Remote login, the intruder is searching for the service of remote login UNIX. In most cases, scanning this port is to find the operating system running on the machine.
Port: 25 Service: SMTP
Description: The port opened by SMTP server is used to send mail. Intruders are looking for SMTP servers to send their spam.
Port: 3 1 service: msg authentication
Description: Trojan Master Paradise and Hacker Paradise open this port.
The above is the explanation of Windows system ports brought to you by Bian Xiao.