Setting up vagrant behind a corporate proxy

Posted: November 28, 2014 in Development process
Tags: , , , , ,

Working on a project where we need more control of our development environment and especially needed a way to make sure that configurations were consistent across all developers machines and our test environment I look into setting up a vagrant environment.

I started out by installing vagrant on my windows machine and after installing I wanted to set up our environment to use  Ubuntu boxes and in the vagrant cloud I found a box I could use named hashicorp/precise64. So to add this box to my local Vagrant environment I ran

$ vagrant box add hashicorp/precise64

Howver the download was blogged by a proxy, so instead I downloaded it and installed from file

$ vagrant box add --name="hashicorp/prcise64" file:///fully/qualified/path/to/file

After adding the box I updated the Vagrantfile to look like this

Vagrant.configure("2") do |config| = "hashicorp/precise64"

To check that everything was working I saved the file and ran

$ vagrant up

This worked like a charm and I followed up with

$ vagrant ssh

but alas this requires an ssh client. Vagrant will suggest several that can be used and I chose to install cygwin

after installing cygwin I ran the ssh command again. and got a ssh session to my default box. Vagrant is smart enough to let you ssh to the default box if there’s just one. When you get to having a multi-machine setup you will need to provide the name of the box you wish to ssh to like so

$ vagrant ssh webserver

to ssh to a box named webserver

By now Id installed

  • Vagrant
  • cygwin

The first thing I wanted to do was update the box so I ran

$ sudo apt-get update

but again this was block by the corporate proxy.

Searching around the net trying to figure out how to configure vagrant to use a given proxy. It turns out there’s a plugin called vagrant-proxyconf and to install plugin ins in vagrant you would typically run

$ vagrant plugin install vagrant-proxyconf

however that still requires vagrant to be able to authenticate towards the proxy so I ended up downloading the gem. The latest version was  version 1.4 which I found on from When you want to install a plugin from source vagrant will let you do so

$ vagrant plugin install vagrant-proxyconf --plugin-source file://fully/qualified/path/vagrant-proxyconf-1.4.0.gem

this will install from the newly downloaded gem instead of those getting around the proxies blocking the usual way to install plugins. So now it was time to set up the proxy for use by the box. This is a simple change to the Vagrantfile

if Vagrant.has_plugin?("vagrant-proxyconf")
    config.proxy.http     = ""
    config.proxy.https    = ""
    config.proxy.no_proxy = "localhost,, 192.168.56.*"

The check to see if the plugin is not required and I found that while debugging it’s actually a good thing not to check because then you will know whether it’s because the installation of the plugin failed or your error is in the configuration itself. However for portability it’s a good thing to check for the plugin. The Vagrantfile is supposed to be something you can share across various environments and some of those might not need the plugin.

So now we should be able to ssh into the box again and update. However for the changes to take place we need to reload the box

$ vagrant reload

and when the reload is done we can ssh to the box again and run apt-get update. However when the proxy requires NTLM authentication this will fail because even though the proxy is now configured correctly for the box it can authenticate and will get a HTTP 407 back. This particular step took me quite sometime to resolve but there’s a solution to the problem called CNTLM. I thought about installing it on the boxes and then repackaging the boxes making them self contained or to install CNTLM on the host. I decided for the latter because I then would have a setup that would allow for other applications to use this same infrastructure. The down side of course being that everyone in the project will need to install CNTLM on their host as well. The installation was pretty strain forward. In the ini file I had to change a few things

  • user name
  • password
  • domain
  • address CNTLM should listen to. If you follow the rest of the examples here it should listen to
  • corporate proxy

After getting it to work I highly recommend to follow the CNTLM recommendation of hashing your credentials

after installing CNTLM I once again opened a ssh-session to the box and once again I was blocked. This time it was not so much the proxy but the network. For the box to be able to connect to the CNTLM proxy I needed to configure a host only network. Which is a network the box can use to communicate with the host and vice verse. It’ rather simple to setup and simply requires a change to the Vagrantfile. Add the below line somewhere in the configuration block "private_network", ip: ""

This will give the box a static IP of and since the host by default will have a static IP of they are on the same subnet and should be able to communicate but we’re not their yet. You will need to setup a firewall rule on the host. There’s a good guide on how to set this up that helped me to be found on

Now with that in place you should finally be able to access the outside world from your vagrant boxes.

To sum up

  1. Download and Install vagrant
  2. Download the box you require from the cloud
  3. Add the box with
    $ vagrant box add --name="name of box" file:///fully/qualified/path/to/file
  4. install cygwin (including the ssh package)
  5. install cntlm and configure it
  6. download vagrant-proxyconf from
  7. install the plugin with
    $ vagrant plugin install vagrant-proxyconf --plugin-source file://fully/qualified/path/vagrant-proxyconf-1.4.0.gem
  8. configure the proxy in the Vagrantfile to point to your CNTLM proxy (see example above)
  9. Add an internal network between guest and host by adding this line to the Vagrantfile "private_network", ip: ""
  10. open the firewall on host for the guest to be able to connect to CNTLM (guide)
  1. Phillipp von Rotenhan says:

    Thanks for the post!

    For some other people stumbling acrosse the same issues with Vagrant and NTLM proxies. The last step with the host-only network configuration can be left out when you set the IP of the proxy to (this is the IP of the host in the defaut Virtualbox configuration). However, you still need to set up the CNTLM on your host.

    Best regards,

    • runefs says:

      I believe the host ip is dependent on the host box. My host ip is by default (win7) but the general idea of setting the host IP as the proxy IP should work regardless of the actual host IP as long as you get it right 🙂

  2. Ken Jones says:

    ideas that may help.
    before trying to install vagrant-proxyconfig run
    export http_proxy=”http://:port”
    export https_proxy=”http://:port”

    example export http_proxy=”″

    go get the cert errors try to install vagrant-proxyconf using

    vagrant plugin install vagrant-proxyconf –plugin-source

    Then use the steps above to configure the proxy server.
    Good luck.

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