Perl Requires Chilkat v11.0.0+

TCP Socket through SSH Tunnel (Port Forwarding)

See more Socket/SSL/TLS Examples

Demonstrates using Chilkat Socket to communicate to a TCP service through an SSH tunnel. This example will connect to an NIST time server and (using the old Time Protocol (RFC 868)), will read the current GMT time.

Note: This is not necessarily a recommended means for getting the current date/time. The most commonly used time protocol is the Network Time Protocol (RFC-1305). The intent of this example is to show how TCP communications can occur through an SSH tunnel.

Chilkat2 Perl

use strict;
use warnings;
use Chilkat2;

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

my $tunnel = Chilkat2::Socket->new;

my $sshHostname = 'sftp.example.com';
my $sshPort = 22;

# Connect to an SSH server and establish the SSH tunnel:
my $success = $tunnel->SshOpenTunnel($sshHostname, $sshPort);
if (!$success) {
    print $tunnel->LastErrorText, "\n";
    exit;
}

# Authenticate with the SSH server via a login/password
# or with a public key.
# This example demonstrates SSH password authentication.
$success = $tunnel->SshAuthenticatePw('mySshLogin', 'mySshPassword');
if (!$success) {
    print $tunnel->LastErrorText, "\n";
    exit;
}

# OK, the SSH tunnel is setup.  Now open a channel within the tunnel.
# Once the channel is obtained, the Socket API may
# be used exactly the same as usual, except all communications
# are sent through the channel in the SSH tunnel.
# Any number of channels may be created from the same SSH tunnel.
# Multiple channels may coexist at the same time.

# Connect to an NIST time server and read the current date/time
my $maxWaitMs = 4000;
my $useTls = 0;
my $channel = Chilkat2::Socket->new;
$success = $tunnel->SshNewChannel('time-c.nist.gov', 37, $useTls, $maxWaitMs, $channel);
if (!$success) {
    print $tunnel->LastErrorText, "\n";
    exit;
}

# The time server will send a big-endian 32-bit integer representing
# the number of seconds since since 00:00 (midnight) 1 January 1900 GMT.
# The ReceiveInt32 method will receive a 4-byte integer, but returns
# 1 or 0 to indicate success.  If successful, the integer
# is obtained via the ReceivedInt property.
my $bigEndian = 1;
$success = $channel->ReceiveInt32($bigEndian);
if (!$success) {
    print $channel->LastErrorText, "\n";
    exit;
}

my $dt = Chilkat2::DateTime->new;
$dt->SetFromNtpTime($channel->ReceivedInt);

# Show the current local date/time
my $bLocalTime = 1;
print 'Current local date/time: ', $dt->GetAsRfc822($bLocalTime), "\n";

# Close the SSH channel.
$success = $channel->Close($maxWaitMs);
if (!$success) {
    print $channel->LastErrorText, "\n";
    exit;
}

# It is possible to create a new channel from the existing SSH tunnel for the next connection:
# Any number of channels may be created from the same SSH tunnel.
# Multiple channels may coexist at the same time.
$success = $tunnel->SshNewChannel('time-a.nist.gov', 37, $useTls, $maxWaitMs, $channel);
if (!$success) {
    print $tunnel->LastErrorText, "\n";
    exit;
}

# Review the LastErrorText to see that the connection was made via the SSH tunnel:
print $tunnel->LastErrorText, "\n";

# Close the connection to time-a.nist.gov.  This is actually closing our channel
# within the SSH tunnel, but keeps the tunnel open for the next port-forwarded connection.
$success = $channel->Close($maxWaitMs);
if (!$success) {
    print $channel->LastErrorText, "\n";
    exit;
}

# Finally, close the SSH tunnel.
$success = $tunnel->SshCloseTunnel();
if (!$success) {
    print $tunnel->LastErrorText, "\n";
    exit;
}

print "TCP SSH tunneling example completed.\n";