1. Check whether the SSH service is installed
#service sshd status
2. Use apt-get to see if SSH can be installed normally
#apt-get install ssh
3. Modify apt source
#cp /etc/apt/sources.list /etc/apt/sources.list.bak
#vi /etc/apt/sources.list
Change all to:
deb http://archive.ubuntu.com/ubuntu/ trusty main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ trusty-security main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ trusty-updates main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ trusty-proposed main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ trusty-backports main restricted universe multiverse
4. Update source
#apt-get update
#apt-get upgrade
5. Install SSH
#apt-get install ssh
If the report version is abnormal, execute it first
#apt-get install openssh-client=1:6.6p1-2ubuntu1