PuTTY – Accessing a Linode Server


PuTTY is a free and open source SSH client for Windows and UNIX systems. It provides easy connectivity to any server running an SSH daemon, so you can work as if you were logged into a console session on the remote system.

  1. Download and run the PuTTY installer from here.
  2. When you open PuTTY, you’ll be shown the configuration menu. Enter the hostname or IP address of your Linode. PuTTY’s default TCP port is 22, the IANA assigned port for for SSH traffic. Change it if your server is listening on a different port. Name the session in the Saved Sessions text bar if you choose, and click Save:

    Saving your connection information.

  3. Click Open to start an SSH session. If you have never previously logged into this system with PuTTY, you will see a message alerting you that the server’s SSH key fingerprint is new, and asking if you want to proceed.

    Do not click anything yet! Verify the fingerprint first.

    PuTTY verify SSH fingerprint

  4. Use Lish to log in to your Linode. Use the command below to query OpenSSH for your Linode’s SSH fingerprint:
    ssh-keygen -E md5 -lf /etc/ssh/ssh_host_ed25519_key.pub
    

    The output will look similar to:

    
    256 MD5:58:72:65:6d:3a:39:44:26:25:59:0e:bc:eb:b4:aa:f7 root@localhost (ED25519)
    

    Note

    For the fingerprint of an RSA key instead of elliptical curve, use: ssh-keygen -lf /etc/ssh/ssh_host_rsa_key.pub.
  5. Compare the output from Step 4 above to what PuTTY is showing in the alert message in Step 3. The two fingerprints should match.
  6. If the fingerprints match, then click Yes on the PuTTY message to connect to your Linode and cache the host fingerprint.

    If the fingerprints do not match, do not connect to the server! You won’t receive further warnings unless the key presented to PuTTY changes for some reason. Typically, this should only happen if you reinstall the remote server’s operating system. If you receive this warning again from a system you already have the host key cached on, you should not trust the connection and investigate matters further.

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