Class: Net::SSH::Gateway

Class | Net::SSH::Gateway
In: | lib/net/ssh/gateway.rb
Parent: | Object

A Gateway is an object that allows you to tunnel network connections through a publicly visible host to a host hidden behind it. This is particularly useful when dealing with hosts behind a firewall. One host will generally be visible (and accessible) outside the firewall, while the others will all be behind the firewall, and the only way to access those restricted hosts is by first logging into the publicly visible host, and from thence logging into the restricted ones.

This class makes it easy to programmatically connect to these restricted hosts via SSH. You can either simply forward a port from the local host to the remote host, or you can open a new Net::SSH connection to the remote host via a forwarded port.

      require 'net/ssh/gateway'

      gateway = Net::SSH::Gateway.new('host.name', 'user')

      gateway.open('hidden.host', 80) do |port|
        Net::HTTP.get_print '127.0.0.1', '/path', port
      end

      gateway.ssh('hidden.host', 'user') do |ssh|
        puts ssh.exec!("hostname")
      end

      gateway.shutdown!

Port numbers are allocated automatically, beginning at MAX_PORT and decrementing on each request for a new port until MIN_PORT is reached. If a port is already in use, this is detected and a different port will be assigned.

### Methods

active? close new open shutdown! ssh

### Classes and Modules

Class Net::SSH::Gateway::Version

### Constants

MAX_PORT | = | 65535 |  | The maximum port number that the gateway will attempt to use to forward connections from.
MIN_PORT | = | 1024 |  | The minimum port number that the gateway will attempt to use to forward connections from.

### Public Class methods

new(host, user, options={})

Instantiate a new Gateway object, using the given remote host as the tunnel. The arguments here are identical to those for Net::SSH.start, and are passed as given to that method to start up the gateway connection.

      gateway = Net::SSH::Gateway.new('host', 'user', :password => "password")

### Public Instance methods

active?()

Returns `true` if the gateway is currently open and accepting connections. This will be the case unless shutdown! has been invoked.

close(port)

Cancels port-forwarding over an open port that was previously opened via open.

open(host, port) {|local_port| ...}

Opens a new port on the local host and forwards it to the given host/port via the gateway host. If a block is given, the newly allocated port number will be yielded to the block, and the port automatically closed (see close) when the block finishes. Otherwise, the port number will be returned, and the caller is responsible for closing the port (close).

      gateway.open('host', 80) do |port|
        # ...
      end

      port = gateway.open('host', 80)
      # ...
      gateway.close(port)

shutdown!()

Shuts down the gateway by closing all forwarded ports and then closing the gateway‘s SSH session.

ssh(host, user, options={}, &block)

Forwards a new connection to the given `host` and opens a new Net::SSH connection to that host over the forwarded port. If a block is given, the new SSH connection will be yielded to the block, and autoclosed when the block terminates. The forwarded port will be autoclosed as well. If no block was given, the new SSH connection will be returned, and it is up to the caller to terminate both the connection and the forwarded port when done.

      gateway.ssh('host', 'user') do |ssh|
        # ...
      end

      ssh = gateway.ssh('host', 'user')
      # ...
      ssh.close
      gateway.close(ssh.transport.port)

[Validate]