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Web Application Proxy and AD FS on AWS
Web Application Proxy and AD FS Quick Start

Overview

Web Application Proxy and AD FS on AWS

Microsoft Active Directory Federation Services (AD FS) is a Windows Server role that provides identity federation and single sign-on (SSO) capabilities for users accessing applications in an AD FS-secured environment, or with federated partner organizations. Put simply, AD FS authenticates users and provides security tokens to applications or federated partner applications that trust AD FS.

For example, you could implement identity federation with AWS Identity and Access Management (IAM) and AD FS, and then use your Active Directory user name and password (instead of the AWS root account or IAM user credentials) to sign in to the AWS Management Console, or to make calls to AWS APIs.

Like domain controllers and other internal server workloads, AD FS servers are deployed in a private virtual private cloud (VPC) subnet. In order to make AD FS accessible to external users, you can deploy the Web Application Proxy role on Windows Server 2012 R2. The Web Application Proxy server can proxy requests to the AD FS infrastructure for users who are connecting from an external location, without the need for VPN connectivity.

You can also use Web Application Proxy to selectively publish and pre-authenticate connections to internal web applications, allowing external users outside your organization to access those applications over the internet.

In this guide, we'll take a look at using your own Active Directory Domain Services (AD DS) infrastructure in AWS, along with AD FS and Web Application Proxy, to provide seamless external access to web applications running in AWS.

Some of the benefits and features of publishing applications with Web Application Proxy and AD FS are:

  • Network isolation – Publishing web applications through Web Application Proxy means that back-end servers are never directly exposed to the internet. You can publish popular web-based workloads such as Microsoft SharePoint, Outlook Web App (OWA), Exchange ActiveSync, Lync (Skype for Business), and even custom web applications through Web Application Proxy.

  • Denial-of-service (DoS) protection – The Web Application Proxy infrastructure uses several mechanisms to implement basic DoS protection, such as throttling and queuing, before routing connections to back-end web applications.

  • Multi-factor authentication – Pre-authentication with AD FS provides support for smart cards, device authentication, and more.

  • Single sign-on (SSO) – This functionality provides users with seamless access to applications without re-prompting for credentials after initial authentication.

  • Workplace Join – Users can connect devices that are not typically domain-joined, such as personal laptops, tablets, and smartphones, to their company's resources. Known devices can be granted conditional access to applications, and you can require that devices register before gaining access to published applications.

For further details, see Planning to Publish Applications Using Web Application Proxy on Microsoft TechNet.

This guide and associated AWS CloudFormation template can be used in conjunction with other AWS Quick Starts to securely publish web applications running on SharePoint, Exchange, Lync, or your own web-based applications. The infrastructure deployed by this Quick Start enables external users to pre-authenticate to AD FS to access these web applications, without exposing the applications or AD FS infrastructure directly to the internet. You can also use this infrastructure to enable federation with AWS.

Cost and Licenses

You are responsible for the cost of the AWS services used while running this Quick Start reference deployment. There is no additional cost for using the Quick Start. See the pricing pages for each AWS service you will be using in this Quick Start for full details.

This Quick Start launches the Amazon Machine Image (AMI) for Windows Server 2012 R2. The AMI is updated on a regular basis with the latest service pack for the operating system, so you don't have to install any updates.

AD FS and Web Application Proxy are server roles within Windows Server 2012 R2. The architecture deployed by this Quick Start does not require any additional licenses from Microsoft. The pay-as-you-go hourly cost for each EC2 instance covers your Windows Server license along with the Web Application Proxy and AD FS components.

There are a number of Microsoft enterprise applications that can be deployed and licensed through the Microsoft License Mobility through Software Assurance program. For development and test environments, you can leverage your existing MSDN licenses using Amazon Elastic Compute Cloud (Amazon EC2) Dedicated Instances. For details, see the MSDN on AWS webpage.

AWS Services

The core AWS components used by this Quick Start include the following AWS services. (If you are new to AWS, see the Getting Started section of the AWS documentation.)

  • Amazon VPC – The Amazon Virtual Private Cloud (Amazon VPC) service lets you provision a private, isolated section of the AWS Cloud where you can launch AWS services and other resources in a virtual network that you define. You have complete control over your virtual networking environment, including selection of your own IP address range, creation of subnets, and configuration of route tables and network gateways.

  • Amazon EC2 – The Amazon Elastic Compute Cloud (Amazon EC2) service enables you to launch virtual machine instances with a variety of operating systems. You can choose from existing Amazon Machine Images (AMIs) or import your own virtual machine images.

  • Amazon EBS – Amazon Elastic Block Store (Amazon EBS) provides persistent block-level storage volumes for use with Amazon EC2 instances in the AWS Cloud. Each Amazon EBS volume is automatically replicated within its Availability Zone to protect you from component failure, offering high availability and durability. Amazon EBS volumes provide the consistent and low-latency performance needed to run your workloads.