Log in to the Linux server via telnet

Note: The
telnet service is installed on the server to prevent the server from being unable to connect to the server again after the ssh service is interrupted, especially when upgrading the ssh service, enable telnet to avoid failure to connect to the server after the ssh upgrade fails, and it is also convenient to quickly restore the ssh service .

step1: Install telnet service on the server

yum install -y telnet-server

step2: Set telnet service status

cat  <<EOF >  /etc/xinetd.d/telnet
service telnet
{
    
    
			flags = REUSE
			socket_type = stream
			wait = no
			user = root
			server = /usr/sbin/in.telnetd
			log_on_failure += USERID
			disable = yes  #改为 no 或者注释这一行
}

step3: configure permissions

**注意：**
默认情况下telnet连接后不能使用超级用户的，要使用超级用户，可以修改配置文件

Comment auth [user_unknown=ignore success=ok ignore=ignore default=bad] pam_securetty.sothis line

step4: Open the telent console (you can add it after the /etc/securetty file)

pts/0
pts/1
pts/2
pts/3
pts/4
pts/5

step4: Start the telnet service

systemctl restart xinetd.service

step5: open log test