16.04 SSH connection refused: hunting down root-cause - Ask Ubuntu

symptoms: 16.04 refuses connection putty , replies ping requests

remedies on askubuntu suggest installing:

sudo apt-get install openssh-server 

before this, how can verify install genuinely needed: i'd verify not configuration obstacle or maybe service needs turned on? there list of checks can performed?

update: does response indicate install required?

user@host:~$ apt-cache policy openssh-server openssh-server:   installed: (none) 

diagnostic credit , muru:

user@host:~$ service ssh status ● ssh.service    loaded: not-found (reason: no such file or directory)    active: inactive (dead) user@host:~$ service ssh start failed start ssh.service: unit ssh.service not found. user@host:~$ apt-cache policy openssh-server openssh-server:   installed: (none)   candidate: 1:7.2p2-4ubuntu2.1   version table:      1:7.2p2-4ubuntu2.1 500         500 http://us.archive.ubuntu.com/ubuntu xenial-updates/main amd64 packages         500 http://security.ubuntu.com/ubuntu xenial-security/main amd64 packages      1:7.2p2-4 500         500 http://us.archive.ubuntu.com/ubuntu xenial/main amd64 packages 

if want connect using ssh, need have ssh running on target system. service ssh status shows doesn't know of such service , apt-cache policy openssh-server shows hasn't been installed @ (installed: (none)). so, yes, have install it.