title: Slow network access to vagrant VM when host connected to wifi
body: <p>I have a VirtualBox image based on Ubuntu 12.04 which is started with the following Vagrantfile:</p>
  
  <pre><code>Vagrant.configure("2") do |config|
    config.vm.box     = "mybox"
    config.vm.box_url = "mybox.box"
    config.vm.network :forwarded_port, guest: 8000, host: 8000
    config.vm.network :private_network, type: "dhcp"
    config.vm.provider :virtualbox do |vb|
      vb.customize ["modifyvm", :id, "--memory", "2048"]
      vb.customize ["modifyvm", :id, "--cpus", "2"]
      vb.customize ["modifyvm", :id, "--natdnshostresolver1", "on"]
      vb.customize ["modifyvm", :id, "--natdnsproxy1", "on"]
    end
  end
  </code></pre>
  
  <p>Access to the guest web server on port 8000 (the forwarded port) can be very slow (~45 kb/s):</p>
  
  <pre><code>curl http://172.28.128.3:8000/file.css &gt; /dev/null
    % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                   Dload  Upload   Total   Spent    Left  Speed
  100  454k  100  454k    0     0  46316      0  0:00:10  0:00:10 --:--:--  118k
  </code></pre>
  
  <p>However, this download speed improves drastically as soon as I disable wifi access on my host machine:</p>
  
  <pre><code>curl http://172.28.128.3:800/file.css &gt; /dev/null
    % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                   Dload  Upload   Total   Spent    Left  Speed
  100  454k  100  454k    0     0  23.5M      0 --:--:-- --:--:-- --:--:-- 24.6M
  </code></pre>
  
  <p>Here is my host network configuration (when wifi is turned on):</p>
  
  <pre><code>$ ifconfig 
  docker0   Link encap:Ethernet  HWaddr 56:84:7a:fe:97:99  
            inet addr:172.17.42.1  Bcast:0.0.0.0  Mask:255.255.0.0
            UP BROADCAST MULTICAST  MTU:1500  Metric:1
            RX packets:0 errors:0 dropped:0 overruns:0 frame:0
            TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
            collisions:0 txqueuelen:0 
            RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)
  
  eth0      Link encap:Ethernet  HWaddr 28:80:23:0a:3b:f7  
            UP BROADCAST MULTICAST  MTU:1500  Metric:1
            RX packets:0 errors:0 dropped:0 overruns:0 frame:0
            TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
            collisions:0 txqueuelen:1000 
            RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)
            Interrupt:20 Memory:d0700000-d0720000 
  
  lo        Link encap:Local Loopback  
            inet addr:127.0.0.1  Mask:255.0.0.0
            inet6 addr: ::1/128 Scope:Host
            UP LOOPBACK RUNNING  MTU:65536  Metric:1
            RX packets:121430 errors:0 dropped:0 overruns:0 frame:0
            TX packets:121430 errors:0 dropped:0 overruns:0 carrier:0
            collisions:0 txqueuelen:0 
            RX bytes:71329608 (71.3 MB)  TX bytes:71329608 (71.3 MB)
  
  vboxnet10 Link encap:Ethernet  HWaddr 0a:00:27:00:00:0a  
            inet addr:172.28.128.1  Bcast:172.28.128.255  Mask:255.255.255.0
            inet6 addr: fe80::800:27ff:fe00:a/64 Scope:Link
            UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
            RX packets:0 errors:0 dropped:0 overruns:0 frame:0
            TX packets:616 errors:0 dropped:0 overruns:0 carrier:0
            collisions:0 txqueuelen:1000 
            RX bytes:0 (0.0 B)  TX bytes:169030 (169.0 KB)
  
  wlan0     Link encap:Ethernet  HWaddr e8:2a:ea:97:84:ed  
            inet addr:192.168.0.102  Bcast:192.168.0.255  Mask:255.255.255.0
            inet6 addr: fe80::ea2a:eaff:fe97:84ed/64 Scope:Link
            UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
            RX packets:1429759 errors:0 dropped:0 overruns:0 frame:0
            TX packets:1428388 errors:0 dropped:0 overruns:0 carrier:0
            collisions:0 txqueuelen:1000 
            RX bytes:507751022 (507.7 MB)  TX bytes:878353259 (878.3 MB)
  </code></pre>
  
  <p>What am I doing wrong?</p>