博客

1、查看当前ssh的版本

[root@qiguangpc local]# ssh -V
OpenSSH_7.4p1, OpenSSL 1.0.2k-fips  26 Jan 2017

2、升级openssh

[root@qiguangpc local]# yum upgrade openssh

3、安装telnet

[root@qiguangpc local]# yum install telnet-server.x86_64 -y

4、启动telnet服务

[root@qiguangpc local]# systemctl enable telnet.socket
Created symlink from /etc/systemd/system/sockets.target.wants/telnet.socket to /usr/lib/systemd/system/telnet.socket.

[root@qiguangpc local]# systemctl start telnet.socket

5、启用root用户登录

如果要使用root用户登录，也是需要在/etc/securetty文件中添加pts终端入口的(pts/0代表登陆的终端第一个，pts/1代表第二个)

[root@qiguangpc local]# vi /etc/securetty

......
pts/0
pts/1
pts/2
pts/3
pts/4
pts/5
pts/6
pts/7
pts/8
pts/9

6、查看zones名称

[root@qiguangpc local]# firewall-cmd --get-active-zones
public
  interfaces: ens33
  
# 查看当前系统所有开放的端口  
[root@qiguangpc local]# firewall-cmd --zone=public --list-ports

7、开放telnet23端口

[root@qiguangpc local]# firewall-cmd --zone