ssh: connect to host gitlab.alpha.com port 22: Network is unreachable

在这里只说明我遇到的问题和解决方法，可能并不能解决你遇到的问题：

git clone git@gitlab.alpha.com:ipcam/ambarella.git
Cloning into 'ambarella'...
ssh: connect to host gitlab.alpha.com port 22: Network is unreachable
fatal: Could not read from remote repository.

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

1、检查网络是否可以ping 通

　　ping xxx.xxx.xxx.xxx

2、查看/etc/network/interfaces

　　address 一栏和要下载的code server是否在同一网段

3、不在同一网段添加路由
　　sudo route add default gw xxx.xxx.xxx.xxx