Imagine having to install an application to 1000 computers manually, then upgrading that application in a few months! Not fun, luckily we can publish (or assign) applications via group policy.

Publishing an application to a user (you can't publish to a computer) is a pretty simple task, and will allow a user to install or uninstall an application. Published applications are optional, and will appear under Add/Remove Programs | Add New Program. To start lets create a new GPO to install the ISA Firewall Client.

Drill down to User Configuration | Software Settings and right-click Software Installation. Select New, then click Package.

Type in the UNC path to the MSI file for the application you wish to install. You MUST use a UNC path!!!!

Next we can specify Published, Assigned (more on this later), or Advanced. We'll click Advanced to see what it offers.

The General tab will allow us to specify the name of the application that will appear in the Add New Program section on the client machines.

The Deployment tab is where we can choose to publish or assign the application, as well as some deployment options.

Auto-install this application by file extension activation would start the installtion procedure when a file extension that you associate with the application is launched. For example if you were to publish Word, you could assignt the DOC extension to it and when a user tries to open a file with the DOC extension, Word would be installed. We can also specify that the application is uninstalled when the user is no longer part of the OU that the application is published to. The Upgrades tab is where we could specify the options for upgrades to existing applications, the Categories tab is where we could add the applications to categories. Categories are useful when publishing large numbers of different applications by allowing you to seperate the applications into groups based on your needs. Once you are happy with the configuration, click OK to publish the application. It will appear in the Software Installation window in the GPO editor.

Close the GPO editor, start a computer that is a member of the domain and login. Open up the Control Panel, click Add/Remove Programs, then select Add New Programs. You should see the application listed.

Click on Add to start the installtion. Once installed, the application listing will tell you that it is installed. You will also see it under Add/Remove Programs.

Software Installation requires Windows Installer packages (MSI files), repackaged files, or .zap files. An MSI file holds the information necessary to describe to the Windows Installer how to set up an application. Most Microsoft applications come with an MSI file but you can create MSI packages with tools from InstallShield or the free tool from VERITAS called WinInstall LE 2003. You can also use a ZAP file. A ZAP file is a text file that provides information about how to install a program, the application properties, and other information required to install the application.