Lianja

Connect to an SFTP Server Through a Jump Host

Demonstrates the Chilkat SFtp.ConnectThroughSsh method, which connects to an SFTP server through an already connected and authenticated Ssh object. The first argument is the jump-host Ssh object, and the second and third are the destination hostname and port.

Background: This is the "jump host" (bastion) pattern: the application connects to a reachable gateway, then tunnels onward to an SFTP server that is only accessible from inside the network. Each hop authenticates separately with its own credentials. The result is a normal SFtp object — still requiring its own authentication and InitializeSftp — that happens to be routed through the first connection.

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llSuccess = .F.

//  Demonstrates the SFtp.ConnectThroughSsh method, which connects to an SFTP server through an
//  already connected and authenticated Ssh object (a jump host).  The 1st argument is the Ssh
//  object, and the 2nd and 3rd are the destination hostname and port.

loSshJump = createobject("CkSsh")

//  Connect and authenticate to the jump host first.
lnPort = 22
llSuccess = loSshJump.Connect("jump.example.com",lnPort)
if (llSuccess = .F.) then
    ? loSshJump.LastErrorText
    release loSshJump
    return
endif

//  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.
lcPassword = "mySshPassword"

llSuccess = loSshJump.AuthenticatePw("myJumpLogin",lcPassword)
if (llSuccess = .F.) then
    ? loSshJump.LastErrorText
    release loSshJump
    return
endif

//  Connect to the SFTP server through the jump host.
loSftp = createobject("CkSFtp")
llSuccess = loSftp.ConnectThroughSsh(loSshJump,"sftp.internal.example.com",lnPort)
if (llSuccess = .F.) then
    ? loSftp.LastErrorText
    release loSshJump
    release loSftp
    return
endif

//  Authenticate to the SFTP server (its own credentials), then initialize SFTP.
llSuccess = loSftp.AuthenticatePw("mySshLogin",lcPassword)
if (llSuccess = .F.) then
    ? loSftp.LastErrorText
    release loSshJump
    release loSftp
    return
endif

llSuccess = loSftp.InitializeSftp()
if (llSuccess = .F.) then
    ? loSftp.LastErrorText
    release loSshJump
    release loSftp
    return
endif

? "Connected to the SFTP server through the jump host."

loSftp.Disconnect()
loSshJump.Disconnect()


release loSshJump
release loSftp