现象

最近pull或者push操作github仓库时，出现kex_exchange_identification: Connection closed by remote host错误，导致无法拉取代码(使用ssh协议)：

# git pull
kex_exchange_identification: Connection closed by remote host
Connection closed by 127.0.0.1 port 7897
fatal: Could not read from remote repository.

Please make sure you have the correct access rights
and the repository exists.

原因

网上找了下，说是因为梯子禁用了22端口，导致无法通过ssh连接github

解决办法

根据github官方文档的说明，可以使用HTTPS的SSH连接来访问github，编辑文件~/.ssh/config加入以下配置，问题即可解决：

Host github.com
    Hostname ssh.github.com
    Port 443
    User git