[Linux] Enable ssh key authentication from one user on client to multiple users on server

Today, I’m trying to setup ssh key authentication, so I can ssh into my server without typing password.

What caught me is that I can’t get key authentication working for the non-root user on server.

For example, I have user

client

on my client and user

server

and

root

on my server.

client@client # ssh server@server
client@client # ssh root@server

I googled it and found the reference here

To sum it up:

On client machine, generate key-pair

ssh-keygen -t rsa

Copy the content of

.ssh/id_rsa.pub

to

/root/.ssh/authorized_keys

and

/home/server/.ssh/authorized_keys

On server machine, modify

/etc/ssh/sshd_config

, uncomment

RSAAuthentication yes
PubkeyAuthentication yes

THIS STEP IS VERY IMPORTANT!!!

Make sure file permissions on a user’s

/home/server/.ssh

directory must be

700

, and the

/home/server/.ssh/authorized_keys

must be

600

On server machine,

systemctl restart sshd