Linux: Installing Openssh-server e:package openssh-server has no installation candidate

$sduo apt-get install openssh-serverreading Package lists ... Donebuilding dependency treereading state information ... Donepackage openssh-server is not a available, but was referred to by another package. This may mean. The package is missing, have been obsoleted, Oris only available from another sourcee:package openssh
   -server has no installation candidate

Execute: sudo apt-get update also prompts for an update failure, or no content to update.

Solution: sudo vim/etc/network/interfaces modify IP, reboot.

Execution: sudo apt-get update

Problem solving:

Http://blog.sina.com.cn/s/blog_3e28c8a50101cax0.html

Linux: Installing Openssh-server e:package openssh-server has no installation candidate