Vagrant Private Network IPs not working, but DHCP does

Vagrant Private Network IPs not working, but DHCP does

I have a vagrant config file with three VMs configured in it. All are
identical except on has a static IP and the other two are on DHCP. The two
which are assigned IPs by DHCP can talk to each other without any issues,
but the one with a static IP cannot be contacted by the others.
In other words ping client0 -> client1 works
ping client1 -> client0 works
ping client1 -> server does not
This is my Vagrantfile:
# -*- mode: ruby -*-
# vi: set ft=ruby :
Vagrant.configure("2") do |config|
config.vm.box = "precise64"
config.vm.box_url = "http://files.vagrantup.com/precise64.box"
config.vm.provision "chef_solo" do |chef|
chef.cookbooks_path = "provision/cookbooks"
chef.add_recipe "apt"
chef.add_recipe "python"
end
config.vm.provision :shell, :path => "provision/python-modules.py"
config.vm.define :server do |server|
server.vm.hostname = "server"
server.vm.network :private_network, ip: "172.28.128.2"
end
config.vm.define :client0 do |client0|
client0.vm.hostname = "client0"
client0.vm.network :private_network, type: :dhcp
end
config.vm.define :client1 do |client1|
client1.vm.hostname = "client1"
client1.vm.network :private_network, type: :dhcp
end
end
Any ideas how I can get the server machine to be contactable by the others
on a static IP? I'm using the virtualbox providor.