云服务器有大大的问题！Ubuntu和CentOS均爆出！

我用ssh 连接 git 仓库， 都会爆出下面的错误，而Ubuntu 和CentOS都是重装过的，重装过立刻执行了下面命令，无任何多余操作：



[root@iZq5Z ~]# ssh -T git@git.coding.net
ssh_exchange_identification: Connection closed by remote host
[root@iZq5Z ~]# ssh -T git@git.oschina.net
Permission denied (publickey).
[root@iZq5Z ~]# ssh -T git@github.com
The authenticity of host 'github.com (192.30.252.129)' can't be established.
RSA key fingerprint is 16:27:ac:a5:76:28:2d:36:63:1b:56:4d:eb:df:a6:48.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added 'github.com,192.30.252.129' (RSA) to the list of known hosts.
Permission denied (publickey).




在Ubuntu 14.4 以及 CentOS 7 中均是这样。