C++

Connect an SSH Tunnel Through a Jump Host

Demonstrates the Chilkat SshTunnel.ConnectThroughSsh method, which connects to an SSH 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 SSH hostname and port.

Background: This chains the tunnel through a "jump host" (bastion): the application reaches a gateway server, then tunnels onward to an SSH server that is only accessible from inside the network. Each hop authenticates separately with its own credentials. The result is a normal SshTunnel — still requiring its own authentication and BeginAccepting — whose transport is routed through the first connection.

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C++

#include <CkSsh.h>
#include <CkSshTunnel.h>

void ChilkatSample(void)
    {
    bool success = false;

    //  Demonstrates the SshTunnel.ConnectThroughSsh method, which connects to an SSH 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 SSH hostname and port.

    CkSsh sshJump;

    //  Connect and authenticate to the jump host first.
    int sshPort = 22;
    success = sshJump.Connect("jump.example.com",sshPort);
    if (success == false) {
        std::cout << sshJump.lastErrorText() << "\r\n";
        return;
    }

    //  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.
    const char *password = "mySshPassword";

    success = sshJump.AuthenticatePw("myJumpLogin",password);
    if (success == false) {
        std::cout << sshJump.lastErrorText() << "\r\n";
        return;
    }

    //  Set up the tunnel and connect to the target SSH server through the jump host.
    CkSshTunnel tunnel;
    tunnel.put_DestHostname("db.internal.example.com");
    tunnel.put_DestPort(5432);

    success = tunnel.ConnectThroughSsh(sshJump,"ssh.internal.example.com",sshPort);
    if (success == false) {
        std::cout << tunnel.lastErrorText() << "\r\n";
        return;
    }

    //  Authenticate to the target SSH server (its own credentials).
    success = tunnel.AuthenticatePw("mySshLogin",password);
    if (success == false) {
        std::cout << tunnel.lastErrorText() << "\r\n";
        return;
    }

    //  After authenticating, call BeginAccepting to start listening for local connections to forward.

    bool waitForThreadExit = true;
    success = tunnel.CloseTunnel(waitForThreadExit);
    if (success == false) {
        std::cout << tunnel.lastErrorText() << "\r\n";
        return;
    }

    sshJump.Disconnect();
    }