Ubuntu – In AWS Ubuntu AMI server refused our key while SSH login

If you have been given the .ppk file by the sysadmin, you can use puttygen to create the ssh key files (install putty-tools from software centre)

Install putty:
sudo apt install putty putty-tools
Create the public key file:
puttygen /path/to/puttykey.ppk -L > ~/.ssh/id_rsa.pub
Create the private key file:
puttygen /path/to/puttykey.ppk -O private-openssh -o ~/.ssh/id_rsa

also, there are some mac instructions which should also work

Note that when running command

puttygen /path/to/puttykey.ppk -O private-openssh -o ~/.ssh/id_rsa

it may ask for password to decrypt the key, plus you should run it as the user which will make the ssh connection so that it stores the key in the correct directory (the ~ symbol is equivalent to the home directory of the current user) Then after checking the chmod permissions are correct you can use

ssh -p 52 user@server.com

Ok, it is fixed however I don't see how this is different from what I tried already.

What I did:

• generate a key pair with puttygen.exe (length: 1024 bits)
• load the private key in the PuTTY profile
• enter the public key in ~/.ssh/authorized_keys in one line (ssh-rsa {your_public_key} with no more than once space between ssh-rsa and your key)
• chmod 700 ~/.ssh
• chmod 600 ~/.ssh/authorized_keys
• chown $USER:$USER ~/.ssh -R
• change /etc/ssh/sshd_config so it contains AuthorizedKeysFile %h/.ssh/authorized_keys
• sudo service ssh restart

For troubleshooting do # tail -f /var/log/auth.log.

Thanks for your help!