$ sudo apt-get install openssh-server
Reading package lists... Done
Building dependency tree
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:
The following packages have unmet dependencies:
openssh-server : Depends: openssh-client (= 1:5.9p1-5ubuntu1)
Recommends: xauth but it is not going to be installed
Recommends: ssh-import-id but it is not going to be installed
E: Unable to correct problems, you have held broken packages.
有人说要卸载掉 openssh-client , 但是 openssh-client 被很多包依赖, 很多的 xserver 的包都依赖它, 这该怎么办好？
搞定, 先装一个依赖的指定版本的 openssh-client (旧版)：
sudo apt-get install openssh-client=1:5.9p1-5ubuntu1
然后再装 openssh-server 就OK了。