Remote control service

SSH（Secure Shell） It is a protocol that can provide remote login in a safe way , It is also the current remote management Linux Preferred method of system . Before that , In general use FTP or Telnet To log in remotely . But because they transmit account passwords and data information over the network in plain text , So it's not safe , It's very vulnerable to man in the middle attacks by hackers , At least tamper with the transmitted data information , Then directly grab the server's account password .

Want to use SSH Protocol to remotely manage Linux System , You need to configure the deployment sshd Service program .sshd Is based on SSH Protocol development of a remote management service , Not only is it easy to use , And it can provide two methods of security verification ：

Password based authentication — Verify login with account and password ;

Key based authentication — You need to generate key pairs locally , Then upload the public key in the key pair to the server , And compare with the public key in the server ; It's safer than that .

It has been emphasized many times before “Linux Everything in the system is a file ”, So in Linux Modify the operating parameters of the service program in the system , In fact, it is in the process of modifying the program configuration file .sshd The configuration information of the service is saved in /etc/ssh/sshd_config In file . The operation and maintenance personnel will generally call the file with the most important configuration information as the main configuration file , Many of the configuration files are marked with pound marks （#） Comment line at the beginning , For these configuration parameters to take effect , You need to remove the previous pound sign after modifying the parameters .