SQL Server

SSH Tunnel Through an Outbound HTTP Proxy

Demonstrates reaching the SSH server through an outbound HTTP proxy using the HttpProxyHostname, HttpProxyPort, HttpProxyUsername, HttpProxyPassword, HttpProxyAuthMethod, and HttpProxyDomain properties.

Background: Many corporate networks force outbound traffic through an HTTP proxy, which reaches non-HTTP services such as SSH via the CONNECT method — so the proxy must be configured to allow CONNECT to the SSH port. HttpProxyAuthMethod is Basic or NTLM, with HttpProxyDomain supplying the Windows domain for NTLM. Note that if SocksVersion is set, the SOCKS proxy takes precedence and these HTTP settings are ignored.

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-- Important: See this note about string length limitations for strings returned by sp_OAMethod calls.
--
CREATE PROCEDURE ChilkatSample
AS
BEGIN
    DECLARE @hr int
    DECLARE @sTmp0 nvarchar(4000)
    DECLARE @success int
    SELECT @success = 0

    --  Demonstrates reaching the SSH server through an outbound HTTP proxy using the SshTunnel
    --  properties HttpProxyHostname, HttpProxyPort, HttpProxyUsername, HttpProxyPassword,
    --  HttpProxyAuthMethod, and HttpProxyDomain.

    DECLARE @tunnel int
    EXEC @hr = sp_OACreate 'Chilkat.SshTunnel', @tunnel OUT
    IF @hr <> 0
    BEGIN
        PRINT 'Failed to create ActiveX component'
        RETURN
    END

    --  The HTTP proxy through which the outbound connection to the SSH server is made.  Common HTTP
    --  proxy ports include 8080 and 3128.  (If SocksVersion is 4 or 5, the SOCKS proxy takes
    --  precedence and these settings are ignored.)
    EXEC sp_OASetProperty @tunnel, 'HttpProxyHostname', 'proxy.example.com'
    EXEC sp_OASetProperty @tunnel, 'HttpProxyPort', 8080

    --  Proxy authentication, if the proxy requires it.  Valid HttpProxyAuthMethod values are "Basic"
    --  and "NTLM".  HttpProxyDomain is the optional Windows domain used for NTLM.
    EXEC sp_OASetProperty @tunnel, 'HttpProxyUsername', 'myProxyLogin'
    EXEC sp_OASetProperty @tunnel, 'HttpProxyPassword', 'myProxyPassword'
    EXEC sp_OASetProperty @tunnel, 'HttpProxyAuthMethod', 'NTLM'
    EXEC sp_OASetProperty @tunnel, 'HttpProxyDomain', 'CORP'

    EXEC sp_OASetProperty @tunnel, 'DestHostname', 'db.internal.example.com'
    EXEC sp_OASetProperty @tunnel, 'DestPort', 5432

    DECLARE @sshPort int
    SELECT @sshPort = 22
    EXEC sp_OAMethod @tunnel, 'Connect', @success OUT, 'ssh.example.com', @sshPort
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @tunnel, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @tunnel
        RETURN
      END

    --  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.
    DECLARE @password nvarchar(4000)
    SELECT @password = 'mySshPassword'

    EXEC sp_OAMethod @tunnel, 'AuthenticatePw', @success OUT, 'mySshLogin', @password
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @tunnel, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @tunnel
        RETURN
      END

    DECLARE @listenPort int
    SELECT @listenPort = 1080
    EXEC sp_OAMethod @tunnel, 'BeginAccepting', @success OUT, @listenPort
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @tunnel, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @tunnel
        RETURN
      END

    PRINT 'Tunnel established through the HTTP proxy.'

    DECLARE @waitForThreadExit int
    SELECT @waitForThreadExit = 1
    EXEC sp_OAMethod @tunnel, 'CloseTunnel', @success OUT, @waitForThreadExit
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @tunnel, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @tunnel
        RETURN
      END

    EXEC @hr = sp_OADestroy @tunnel


END
GO