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VMware Horizon View

Duo integrates with VMware Horizon View 5.1 and newer to add two-factor authentication with passcodes to VMware View client login.

This configuration allows use of passcodes to authenticate to VMware View, as well as Duo's push and phone call authentication and SMS.

First Steps

To integrate Duo with your VMware View Server, you will need to install a local proxy service on a machine within your network. Before proceeding, you should locate (or set up) a system on which you will install the Duo Authentication Proxy. The proxy supports Windows and Linux systems (in particular, we recommend Windows Server 2012 R2 or later, Red Hat Enterprise Linux 6 or later, CentOS 6 or later, or Debian 6 or later).

This Duo proxy server also acts as a RADIUS server — there's no need to deploy a separate RADIUS server to use Duo.

Then you'll need to:

  1. Sign up for a Duo account.
  2. Log in to the Duo Admin Panel and navigate to Applications.
  3. Click Protect an Application and locate VMware View in the applications list. Click Protect this Application to get your integration key, secret key, and API hostname. See Getting Started for help.
Connectivity Requirements

This integration communicates with Duo's service on TCP port 443. Also, we do not recommend locking down your firewall to individual IP addresses, since these may change over time to maintain our service's high availability.

Install the Duo Authentication Proxy

The Duo Authentication Proxy can be installed on a physical or virtual host. We recommend a system with at least 1 CPU, 200 MB disk space, and 4 GB RAM (although 1 GB RAM is usually sufficient).

  1. Download the most recent Authentication Proxy for Windows from https://dl.duosecurity.com/duoauthproxy-latest.exe. Note that the actual filename will reflect the version e.g. duoauthproxy-2.4.19.exe.
  2. Launch the Authentication Proxy installer on the target Windows server as a user with administrator rights and follow the on-screen prompts.
  1. Ensure that OpenSSL, Python 2.6 or 2.7 (including development headers and libraries), and a compiler toolchain are installed. On most recent RPM-based distributions — like Fedora, RedHat Enterprise, and CentOS — you can install these by running (as root):

    $ yum install gcc make openssl-devel python-devel libffi-devel

    On Debian-derived systems, install these dependencies by running (as root):

    $ apt-get install build-essential libssl-dev python-dev libffi-dev

    To ensure that your Python version will work with the Authentication Proxy, run:

    $ python --version

    If the output does not say "Python 2.6.x" or "Python 2.7.x", first take note that many distributions can support multiple versions of python simultaneously. If your python installation does not appear to be a supported version, try replacing "python" in the above command with "python2.6" or "python2.7". If neither of these work, then you will need to install a different version of Python. You may need to search additional repositories for your distribution (e.g. for Centos or Red Hat Enterprise Linux, Extra Packages for Enterprise Linux), or build Python from source.

  2. Download the most recent Authentication Proxy for Unix from https://dl.duosecurity.com/duoauthproxy-latest-src.tgz. Depending on your download method, the actual filename may reflect the version e.g. duoauthproxy-2.4.19-src.tgz.

  3. Extract the Authentication Proxy files and build it as follows:

    $ tar xzf duoauthproxy-latest-src.tgz
    $ cd duoauthproxy-version-src
    $ export PYTHON=python_command
    $ make
    Where python_command is the command to run a Python 2.6 or Python 2.7 interpreter (e.g. "python", "python2.6", "python2.7").
  4. Install the authentication proxy (as root):

    $ cd duoauthproxy-build
    $ ./install

    Follow the prompts to complete the installation.

If you ever need to uninstall the proxy, run /opt/duoauthproxy/uninstall.

Configure the Proxy

After the installation completes, you will need to configure the proxy.

The Duo Authentication Proxy configuration file is named authproxy.cfg, and located in the conf subdirectory of the proxy installation. With default installation paths, the proxy configuration file will be located at:

Platform Default Configuration Path
Windows (64-bit) C:\Program Files (x86)\Duo Security Authentication Proxy\conf\authproxy.cfg
Windows (32-bit) C:\Program Files\Duo Security Authentication Proxy\conf\authproxy.cfg
Linux /opt/duoauthproxy/conf/authproxy.cfg

The configuration file is formatted as a simple INI file. Section headings appear as:

[section]

Individual properties beneath a section appear as:

name=value

The Authentication Proxy may include an existing authproxy.cfg with some example content. For the purposes of these instructions, however, you should delete the existing content and start with a blank text file. We recommend using WordPad or another text editor instead of Notepad when editing the config file on Windows.

Configure the Proxy for Duo Only Authentication

At the top of your authproxy.cfg, create a [duo_only_client] section. This section has no additional parameters to configure.

[duo_only_client]

When using the [duo_only_client] configuration, the Authentication Proxy will ignore primary credentials and perform Duo factor authentication only.

Configure the Proxy for Your VMware View Server

Next, we'll set up the Authentication Proxy to work with your VMware View Server. Create a [radius_server_challenge] section with the following properties:

Required

ikey Your integration key.
skey Your secret key.
api_host Your API hostname (e.g. "api-XXXXXXXX.duosecurity.com").
radius_ip_1 The IP address of your VMware View Server.
radius_secret_1 A secret to be shared between the proxy and your VMware View Server. If you're on Windows and would like to encrypt this secret, see Encrypting Passwords in the full Authentication Proxy documentation.
client

The mechanism that the Authentication Proxy should use to perform primary authentication. This should correspond with a "client" section elsewhere in the config file.

"ad_client" Use Active Directory for primary authentication. Make sure you have an [ad_client] section configured.
"radius_client" Use RADIUS for primary authentication. Make sure you have a [radius_client] section configured.
"duo_only_client" Do not perform primary authentication. Make sure you have a [duo_only_client] section configured.

This parameter is optional if you only have one "client" section. If you have multiple, each "server" section should specify which "client" to use.

Optional

port The port on which to listen for incoming RADIUS Access Requests. Default: 1812.
failmode

Either "safe" or "secure":

"safe" In the event that Duo's service cannot be contacted, users' authentication attempts will be permitted if primary authentication succeeds. This is the default.
"secure" In the event that Duo's service cannot be contacted, all users' authentication attempts will be rejected.

A completed config file, with no primary authenticator, should look something like:

[duo_only_client]
 
[radius_server_challenge]
ikey=DIXXXXXXXXXXXXXXXXXX
skey=XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
api_host=api-XXXXXXXX.duosecurity.com
failmode=safe
client=duo_only_client
radius_ip_1=5.6.7.8
radius_secret_1=thisisalsoaradiussecret
port=1812

Make sure to save your configuration file when done.

Note

View video guides for proxy deployment at the Authentication Proxy Overview or see the Authentication Proxy Reference Guide for additional configuration options.

Start the Proxy

Open an Administrator command prompt and run:

net start DuoAuthProxy

Alternatvely, open the Windows Services console (services.msc), locate "Duo Security Authentication Proxy Service" in the list of services, and click the Start Service button.

If the service starts successfully, Authentication Proxy service output is written to the authproxy.log file, which can be found in the log subdirectory.

If you see an error saying that the "service could not be started", open the Application Event Viewer and look for an Error from the source "DuoAuthProxy". The traceback may include a "ConfigError" that can help you find the source of the issue.

Stop and restart the Authentication Proxy service by either clicking the Restart Service button in the Windows Services console or issuing these commands from an Administrator command prompt:

net stop DuoAuthProxy & net start DuoAuthProxy

Open a root shell and run:

# /opt/duoauthproxy/bin/authproxyctl start

To ensure the proxy started successfully, run:

# /opt/duoauthproxy/bin/authproxyctl status

Authentication Proxy service output is written to the authproxy.log file, which can be found in the log subdirectory.

To stop and restart the Authentication Proxy, open a root shell and run:

# /opt/duoauthproxy/bin/authproxyctl restart

Configure VMware View

Configure Your VMware View Connection Server

  1. Log in to the VMware View administrative interface.
  2. Navigate to View Configuration → Servers → Connection Servers in the administrative interface.
  3. Select the connection server that you want to protect and click Edit.
  4. Click on the Authentication tab.
  5. Select RADIUS in the "2-factor authentication" drop-down list:
  6. Enable "Use the same user name and password for RADIUS and Windows authentication".
  7. Select Create New Authenticator in the Authenticator drop-down list:
  8. Add a New Authenticator with the following information:
    Hostname/Address The IP address of your Duo Authentication Proxy
    Authentication Port (Default Radius for 1812)
    Accounting Port 0
    Authentication type PAP
    Shared secret The RADIUS secret shared with your Duo Authentication Proxy
    Server Timeout 30 seconds
  9. Optional: VMware View allows you to configure a Secondary Authentication Server.

Test Your Setup

  1. Start Your VMware View Client and enter your primary credentials (make sure you've already enrolled in Duo).

    VMware View Client

  2. After you enter your username and password, a second window prompts you for a next response (the passcode field).

    VMware View Client

    Horizon View client version 6.0 and later display an enhanced challenge prompt, listing your available factors (or an enrollment URL).

    VMware View Client 6.0

In the passcode field you may enter a passcode or choose from the following factor names by typing the word:

push Perform Duo Push authentication
You can use Duo Push if you've installed Duo Mobile and added your account to it
phone Perform phone callback authentication
sms Send a new batch of SMS passcodes
Your authentication attempt will be denied. You can then authenticate with one of the newly-delivered passcodes.

If you wanted to use Duo Push (rather than a passcode) to authenticate, you would enter:

username: bob
password: password
passcode: push

You can also specify a number after the factor name if you have more than one device enrolled. So you can enter phone2 or push2 if you have two phones enrolled.

Troubleshooting

Need some help? Take a look at the View Frequently Asked Questions (FAQ) page or try searching our Knowledge Base articles or Community discussions. For further assistance, contact Support.

Network Diagram

  1. Primary authentication initiated to application or service
  2. Primary authentication using Active Directory or RADIUS
  3. VMware View sends authentication request to Duo Security’s authentication proxy
  4. Duo authentication proxy connection established to Duo Security over TCP port 443
  5. Secondary authentication via Duo Security’s service
  6. Duo authentication proxy receives authentication response
  7. VMware View access granted

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