B4X

Get SSH Server Authentication Methods

Demonstrates getting the authentication methods advertised by an SSH server. Connect first but do not authenticate, then call GetAuthMethods, which returns a lowercase, comma-separated list such as publickey,password,keyboard-interactive.

Important: Querying the authentication methods intentionally disconnects from the server, so reconnect before authenticating.

Background: Knowing what a server accepts lets a client choose the right authentication path rather than guessing — for example, falling back to keyboard-interactive when password authentication is not offered, or failing fast with a clear message when only public-key is allowed. It is also useful diagnostically when authentication fails for reasons that are not obvious from the error text.

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Dim success As Boolean = False

'  This example requires the Chilkat API to have been previously unlocked.
'  See Global Unlock Sample for sample code.

'  Demonstrates getting the authentication methods advertised by an SSH server.

Dim ssh As ChilkatSsh
ssh.Initialize("ssh")

Dim port As Int = 22

'  The server must be connected, but not yet authenticated.
success = ssh.Connect("ssh.example.com", port)
If success = False Then
    Log(ssh.LastErrorText)
    Return
End If


'  Returns a lowercase, comma-separated list, such as:
'      publickey,password,keyboard-interactive
Dim authMethods As String = ssh.GetAuthMethods
If ssh.LastMethodSuccess = False Then
    Log(ssh.LastErrorText)
    Return
End If

Log("Authentication methods supported by this server: " & authMethods)

'  IMPORTANT: Querying the authentication methods intentionally disconnects from the server.
'  Reconnect before authenticating.
success = ssh.Connect("ssh.example.com", port)
If success = False Then
    Log(ssh.LastErrorText)
    Return
End If


'  Normally you would not hard-code the password in source.  You should instead obtain it
'  from an interactive prompt, environment variable, or a secrets vault.
Dim password As String = "mySshPassword"

success = ssh.AuthenticatePw("mySshLogin", password)
If success = False Then
    Log(ssh.LastErrorText)
    Return
End If


Log("SSH authentication successful.")

ssh.Disconnect