Linux安装OpenSSH-Server出错：
$sduo apt-get install openssh-server
Reading package lists… Done
Building dependency tree
Reading state information… Done
Package openssh-server is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source
E: Package openssh-server has no installation candidate
执行:sudo apt-get update 也提示更新失败，或者无内容可更新。
解决方案：sudo vim /etc/network/interfaces修改ip，重启。
执行：sudo apt-get update
问题解决：
