Port forwarding documentation

docs/getting-started/ports.md

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+---
+layout: getting_started
+title: Getting Started - Port Forwarding
+---
+# Port Forwarding
+
+So we now have this virtual environment running all these servers
+and processes. Great! But what's the use if we can't access them from
+our _outside_ of the virtual environment? Well, it turns out Vagrant has
+a built-in feature to handle just that: port forwarding.
+
+Port forwarding allows you to specify ports on the host machine to forward
+to the guest machine. This allows you to access your web services using
+your own browser on your machine while the server actually sits and runs
+within a virtual machine.
+
+## Creating a Forwarded Port
+
+In our case, we just want to forward Apache. Port forwarding is specified
+in the Vagrantfile, like so:
+
+{% highlight ruby %}
+Vagrant::Config.run do |config|
+  # Forward guest port 80 to host port 4567 and name the mapping "web"
+  config.vm.forward_port("web", 80, 4567)
+end
+{% endhighlight %}
+
+`forward_port` is a method which takes three arguments:
+
+* **name** - A name of the mapping. This name must be unique, otherwise
+  if its repeated it will be overwritten. This name is only used internally.
+* **guest port** - The port on the virtual machine
+* **host port** - The port on your local machine you want forwarded
+
+## Applying Forwarded Ports
+
+Forwarded ports are applied during `vagrant up` like any other configuration.
+But if you already have a running system, calling `vagrant reload` will
+apply them without re-importing and re-building everything.
+
+Note that forwarding ports requires a virtual machine restart since VirtualBox
+won't pick up on the forwarded ports until it is completely restarted.