Publishing Exchange Outlook Web App (OWA)

Introduction

Forefront Threat Management Gateway (TMG) 2010 includes support for publishing Microsoft Exchange Outlook Web App (OWA) for Exchange 2010, as well as Outlook Web Access for Exchange 2007, 2003, and 2000. In this second part of the article series we will walk through the steps required to publish Exchange OWA 2010 using TMG.

Importing the Certificate

Before we can publish OWA, we first need to import the SSL certificate for the site on the TMG firewall. To accomplish this, click Start / Run and then type mmc.exe. From the drop down menu choose File / Add/Remove Snap-in. Select Certificates, then click Add >.

Figure 1
Select the Computer Account option.

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Select the option to manage the Local computer.

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In the console tree, expand the Certificates node. Expand the Personal folder, then right-click the Certificates folder and choose Import…

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Enter the location of the certificate file you exported previously.

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Enter the password and optionally mark the private key exportable.

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Accept the default option to Place all certificates in the following store.

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In the TMG management console, right-click the Firewall Policy node in the console tree and choose New, then Exchange Web Client Access Publishing Rule…

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Give the publishing rule a descriptive name.

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Select Exchange Server 2010 from the drop down list, and then select the option to publish Outlook Web Access.

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For demonstration purposes we are publishing a single CAS server, so we’ll choose the option to Publish a single web site or load balancer.

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Select the option to Use SSL to connect to the published web server or server farm.

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Enter the name of the internal web site.

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Select the option to accept requests for a specific domain, and then enter the public name of the web site.

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Create a web listener for the site by selecting New…, and then enter a descriptive name for the listener.

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Select the option to Require SSL secure connection with clients.

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Select the network to listen for incoming web requests.

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Choose Select Certificate… and select the certificate you imported previously.

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Select the option to use HTML Form Authentication and Windows (Active Directory) to validate credentials.

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If required, enable SSO.

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The authentication method used by TMG must match the authentication method configured on the web site. Since we enabled basic authentication on the web site, we’ll choose Basic Authentication here.

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If you wish to grant access to OWA only to specific users and/or groups, add them here. Otherwise accept the default All Authenticated Users group.

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To confirm operation, click the Test Rule button.

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TMG will test the rule and report the success or failure accordingly.

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