[root@node01 ~]# ssh node02
ssh_exchange_identification: Connection closed by remote host

修改连接数无效

[root@node02 denyhosts]# vi /etc/hosts.allow

加入node01

sshd:node01

ssh-keygen -R [hostname] 删除~/.ssh/known_hosts中关于服务器旧的ssh免密登录密钥