CENTOS 7 telnet 服务安装
开篇废话 telnet 很重要,当升级ssh失败时,无法通过ssh连接服务器时需要用 telnet 连接。
1 安装telnet-server
1.1 yum install telnet xinetd telnet-server -y
1.2 离线安装? http://rpmfind.net/linux/rpm2html/search.php?query=xinetd
下载 xinetd telnet-server telnet 3个包 并上传至服务器
安装命令? --nodeps强制安装
rpm -ivh xinetd-2.3.15-14.el7.x86_64.rpm --nodeps
rpm -ivh telnet-0.17-65.el7_8.x86_64.rpm --nodeps
rpm -ivh telnet-server-0.17-65.el7_8.x86_64.rpm --nodeps
配置telnet登录的终端类型,在/etc/securetty文件末尾增加一些pts终端,如下------不配置root无法登陆
vi /etc/securetty
pts
/0
pts
/1
pts
/2
pts
/3
# systemctl enable xinetd.service
# systemctl enable telnet.socket
启动命令?
systemctl start telnet.socket
systemctl start xinetd(或service xinetd start)
停止命令
systemctl stop telnet.socket
systemctl stop xinetd
重启
![](https://img2020.cnblogs.com/blog/1409922/202011/1409922-20201126153747937-1038865520.png)
---到这里就不怕ssh有问题连不上了。
问题排查 1 systemctl status telnet.socket --查看服务器启动状态
2 tail /var/log/secure
升级成功后需要关闭telnet ? ---telnet 是协议是TCP/IP协议族中的一员 是不安全的的。
关闭方法:
rpm -qa |grep telnet
telnet-server-0.17-66.el7.x86_64
telnet-0.17-66.el7.x86_64
[root@CUEBWX ~]# rpm -e telnet-server-0.17-66.el7.x86_64
[root@CUEBWX ~]# rpm -e telnet-0.17-66.el7.x86_64
[root@CUEBWX ~]# rpm -qa |grep xinetd
xinetd-2.3.15-14.el7.x86_64
[root@CUEBWX ~]# rpm -e xinetd-2.3.15-14.el7.x86_64
测试是否关闭?
telnet 127.0.0.1 23
-bash: /bin/telnet: No such file or directory
[root@CUEBWX ~]# ps -ef |grep telnet
root 30737 30290 0 13:42 pts/1 00:00:00 telnet 127.0.0.1 23
root 30738 1 0 13:42 ? 00:00:00 in.telnetd: localhost
root 31061 30748 0 13:57 pts/3 00:00:00 vi /etc/xinetd.d/telnet
root 31606 30748 0 14:13 pts/3 00:00:00 grep --color=auto telnet
[root@CUEBWX ~]# kill -9 30737Killed
[root@CUEBWX ~]# ps -ef |grep telnet
root 31646 30290 0 14:14 pts/1 00:00:00 grep --color=auto telnet
CENTOS 6
vi /etc/xinetd.d/telnet
将”disable= yes”改成” disable=no”
service xinetd restart 重启