title: Centos7 with private network lost fixed IP
body: <p>I've a network issue with a centos7 vagrant box.
  When I setup a private network, with fixed IP, this one is well binding first, but get lost after some seconds/minutes.</p>
  
  <pre><code> vagrant up
   ==&gt; default: Forcing shutdown of VM...
   ==&gt; default: Destroying VM and associated drives...
   ==&gt; default: Running cleanup tasks for 'shell' provisioner...
   Bringing machine 'default' up with 'virtualbox' provider...
   ==&gt; default: Importing base box 'sfeirbenelux/centos7'...
   ==&gt; default: Matching MAC address for NAT networking...
   ==&gt; default: Checking if box 'sfeirbenelux/centos7' is up to date...
   ==&gt; default: Setting the name of the VM: poc_docker
   ==&gt; default: Fixed port collision for 22 =&gt; 2222. Now on port 2200.
   ==&gt; default: Clearing any previously set network interfaces...
   ==&gt; default: Preparing network interfaces based on configuration...
       default: Adapter 1: nat
       default: Adapter 2: hostonly
   ==&gt; default: Forwarding ports...
       default: 22 =&gt; 2200 (adapter 1)
   ==&gt; default: Running 'pre-boot' VM customizations...
   ==&gt; default: Booting VM...
   ==&gt; default: Waiting for machine to boot. This may take a few minutes...
       default: SSH address: 127.0.0.1:2200
       default: SSH username: vagrant
       default: SSH auth method: private key
       default: Warning: Connection timeout. Retrying...
       default:
       default: Vagrant insecure key detected. Vagrant will automatically replace
       default: this with a newly generated keypair for better security.
       default:
       default: Inserting generated public key within guest...
       default: Removing insecure key from the guest if its present...
       default: Key inserted! Disconnecting and reconnecting using new SSH key...
   ==&gt; default: Machine booted and ready!
   ==&gt; default: Checking for guest additions in VM...
       default: The guest additions on this VM do not match the installed version of
       default: VirtualBox! In most cases this is fine, but in rare cases it can
       default: prevent things such as shared folders from working properly. If you see
       default: shared folder errors, please make sure the guest additions within the
       default: virtual machine match the version of VirtualBox you have installed on
       default: your host and reload your VM.
       default:
       default: Guest Additions Version: 5.0.2
       default: VirtualBox Version: 4.3
   ==&gt; default: Setting hostname...
   ==&gt; default: Configuring and enabling network interfaces...
   ==&gt; default: Running provisioner: shell...
       default: Running: inline script
   ==&gt; default: net.ipv4.ip_forward = 1
   ==&gt; default: Setting up swapspace version 1, size = 2097148 KiB
   ==&gt; default: no label, UUID=170723d8-1782-4915-a877-4d9874ac7396
   ➜  install git:(master) ✗ ping 192.168.100.20
   PING 192.168.100.20 (192.168.100.20): 56 data bytes
   64 bytes from 192.168.100.20: icmp_seq=0 ttl=64 time=0.390 ms
   64 bytes from 192.168.100.20: icmp_seq=1 ttl=64 time=0.252 ms
   64 bytes from 192.168.100.20: icmp_seq=2 ttl=64 time=0.461 ms
   ^C
   --- 192.168.100.20 ping statistics ---
   3 packets transmitted, 3 packets received, 0.0% packet loss
   round-trip min/avg/max/stddev = 0.252/0.368/0.461/0.087 ms
   ➜  install git:(master) ✗ ping 192.168.100.20
   PING 192.168.100.20 (192.168.100.20): 56 data bytes
   64 bytes from 192.168.100.20: icmp_seq=0 ttl=64 time=0.273 ms
   Request timeout for icmp_seq 1
   Request timeout for icmp_seq 2
   Request timeout for icmp_seq 3
   Request timeout for icmp_seq 4
  </code></pre>
  
  <p>With this vagrant file :</p>
  
  <pre><code>vagrant.configure(2) do |config|
  
   config.vm.box = "centos7"
   config.vm.hostname = "docker-registry"
   config.vm.box_url = "https://github.com/holms/vagrant-centos7-box/releases/download/7.1.1503.001/CentOS-7.1.1503-x86_64-netboot.box"
  
   #config.vm.network "public_network"
   config.vm.network "private_network", ip: "192.168.100.20"
   #config.vm.synced_folder ".", "/vagrant", type: "nfs"
  
   # VirtualBox
   config.vm.provider :virtualbox do |vb|
     vb.name = "poc_docker"
     vb.memory = 3072
     vb.cpus = 2
     vb.customize ["modifyvm", :id, "--natdnshostresolver1", "on"]
     vb.customize ["modifyvm", :id, "--natdnsproxy1", "on"]
   end
  
  
  end
  </code></pre>
  
  <p>When I connect on the box, it seems that the ip is lost.</p>
  
  <pre><code>sudo /sbin/ifup eth1
  </code></pre>
  
  <p>Fix the problem temporary, but the IP get losts sometime again.
  Rebooting the box (vagrant halt &amp;&amp; vagrant up) seem to fix the problem permanently.
  I've try to create a custom centos 7 box with Packer ( <a href="https://atlas.hashicorp.com/sfeirbenelux/boxes/centos7" rel="noreferrer">https://atlas.hashicorp.com/sfeirbenelux/boxes/centos7</a>), and I reproduce the issue too.</p>
  
  <p>I suppose that's a Centos 7 specific issue ? 
  Do you already have the same problem ? Is there a way to fix this by adding a vagrant command ?</p>
  
  <p>My environment :</p>
  
  <p>OS X Yosemite
  ➜  ~  vagrant --version
  Vagrant 1.7.2
  ➜  ~  VBoxManage --version
  4.3.26r98988</p>