openssh8.4p1升级步骤和安装包
## telnet安装
### centos 7
yum install telnet-server.x86_64
yum install telnet.x86_64
yum install xinetd.x86_64
systemctl start telnet.socket
systemctl start xinetd
### centos 6
yum install xinetd
yum install telnet
yum install telnet-server
service xinetd start
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