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Using Public Key Authentication to Establish an SSH Connection with PuTTY

For Cloud Servers and Dedicated Servers managed in the Cloud Panel

In this article, we'll show you how to use PuTTY to establish an SSH connection between your local computer and your server using public key authentication.

PuTTY is a free program for Windows operating systems that allows you to establish an encrypted network connection to your server using SSH. Plus, you can use PuTTY to execute commands directly on your server from the command line.

Requirements

  • You have entered the private key in the Security > SSH Keys section of the Cloud Panel to create a key pair. Alternatively, you have stored the public key of an existing key pair in the Cloud Panel.

  • You saved the private key on your local computer.

  • You created a server. When you selected the configuration, you added an SSH key under Advanced Options > New SSH Key. You also have the private key for this SSH key.

Downloading PuTTY

To use public key authentication, you need the PuTTY and PuTTYgen programs. To download these programs to your local computer, do the following:

  • Open the following URL in your browser:

    https://www.chiark.greenend.org.uk/~sgtatham/putty/latest.html

  • In the Alternative binary files section under putty.zip (a .ZIP archive of all the above), select the appropriate version for your local computer's operating system and download it.

  • Open Windows Explorer and go to the folder where the downloaded ZIP file is located.

  • If necessary, copy it to the desired folder and decompress the ZIP file.

Converting the Private Key From the SSH Key with PuTTYgen

  • Open the folder where you unzipped the PuTTY and PuTTYgen programs.

  • Start PuTTYgen.

  • Click File > Load private key.

Screenshot: PuTTY Key Generator mit hervorgehobener Option Load private key im Menü File
Abbildung: Option Load private key unter dem Menü File für die Konvertierung von privaten Schlüsseln

  • In the Load private key: window, select All Files (*.*) in the lower right corner.

  • Select the private key and click Open.

    The following message is displayed:

Screenshot: PuTTYgen-Dialogfenster mit der Meldung über den erfolgreichen Import eines Fremdschlüssels und der Anweisung, ihn im PuTTY-Format zu speichern.
Abbildung: Fenster PuTTYgen Notice mit der Aufforderung, den privaten Schlüssel im PuTTY-Format zu speichern.

  • Click OK.

  • Optional: In the Key passphrase field, type a password and repeat it.

  • Make sure that RSA is selected in the Parameters area.

  • Click Save private key.

Screenshot: PuTTY Key Generator mit ausgefüllten Feldern für Key-Kommentar und Passphrase; Schaltfläche "Save private key" hervorgehoben.
Abbildung: Option "Save private key" in PuTTYgen zur Speicherung des generierten privaten Schlüssels mit Passphrase

  • Select the desired folder.

  • Enter the desired file name and click Save.

Establishing an SSH Connection to the Server

  • Start PuTTY.

  • In the Hostname (or IP address) field, enter the IP address of your servers.

Screenshot: PuTTY-Konfigurationsfenster mit eingegebener Host-IP-Adresse und ausgewähltem Verbindungstyp SSH.
Abbildung: Fenster PuTTY Configuration mit eingetragener IP-Adresse im Feld Hostname (or IP address)

  • Under Category > Connection, click Data.

  • In the Auto-login username field, type the user name.

Screenshot: Das PuTTY-Konfigurationsfenster wird angezeigt. In diesem Fenster ist das Feld Auto-login username hervorgehoben. In dem Feld ist der Benutzername root eingetragen.
Abbildung: Fenster PuTTY Configuration mit dem Auto-Login-Benutzernamen root

  • Under Category > Connection > SSH, click Auth.

  • Under Private key file for authentication:, click Browse....

Screenshot: Im PuTTY-Konfigurationsmenü im Bereich Authentication parameters ist Schaltfläche Browse zum Auswählen der privaten Schlüsseldatei für die Authentifizierung hervorgehoben.
Abbildung: PuTTY-Konfigurationsfenster mit hervorgehobener Schaltfläche Browse... für die Auswahl der privaten Schlüsseldatei.

  • Select the private key and click Open.

  • To establish the SSH connection, click Open.

Please Note

A warning message appears during the first login. Since the SSH server was previously unknown, PuTTY does not have a key.

  • To allow the connection and save the key for future sessions, click Accept.

Screenshot: Das Fenster PuTTY Security Alert wird angezeigt. In diesem Fenster ist die Schaltfläche Accept hervorgehoben, mit der man den Host-Schlüssel bestätigt und speichert.
Abbildung: Bei der ersten Verbindung zeigt PuTTY das Fenster PuTTY Security Alert, um den Host-Schlüssel zu akzeptieren und zu speichern.

The SSH connection should now be successfully established.

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