how to access to apache running inside vagrant with mobile phone?

Question

I am running apache2 on a vagrant machine with the following vagrantfile (as desribed here):

Vagrant.configure("2") do |config|
  config.vm.box = "precise32"
  config.vm.box_url = "http://files.vagrantup.com/precise32.box"
  config.vm.synced_folder "./app", "/var/www/", create:true
  config.vm.network :private_network, ip: "192.168.55.55"
  config.vm.provision :shell, :path => "setup.sh"

  config.ssh.username = "vagrant"
  config.ssh.password = "vagrant"

  config.vm.provider :virtualbox do |vb|
    vb.gui = true
  end
end

setup.sh:

sudo apt-get -y update
sudo apt-get -y install apache2 php5 libapache2-mod-php5
sudo service apache2 restart

I am able to access from my host machine to address 192.168.55.55 and see the index page.

My question is what do I need to change (or add) in order to be able to access this page from my mobile phone on both cases:

1. When the mobile phone is connected to the same LAN (through WiFi) of the host machine.
2. When the mobile phone is not connected to the same LAN.

Do I need to add a rule of port forwarding inside my router?

Thanks in advance