An Installer may either install for all users to use or for just the current user. When it is installed for all users it is called an Administrative install. The behavior of an msi or msp file varies depending on whether Windows has User Access Control (UAC) enabled or not. In Windows 7 and later additions of Windows, it is not possible in the standard Windows UAC configuration to switch off UAC completely. Thus dealing with UAC completely switched off is not discussed here. It is presumed that at least the lowest level of UAC is enabled.
When UAC is on, Installer files will by default only be able to install for the current user. Administrative installs are not possible unless one of 3 things occurs:
When an Installer file has elevation built in there is usually nothing special to do. Refer to 21.1.1 Double-click the Installer file in Windows Explorer for more details. The discussion below describes the exceptions which occur when the Installer file needs to configure IIS.
The MSI install will be marked to be run Elevated if it needs to be able to have an administration rights to perform the install. E.g. the Listener needs to be installed or a web site needs to be created.
If IIS configuration is not required by the MSI, I the MSI may be run by either an administrator or a non- administrator user (provided the administrator user id and password are known).
When IIS needs to be configured, then there are some restrictions and caveats.
If IIS is not installed, the MSI may be run by either an administrator or non- administrator user. It defaults the website details and PRESUMES it does not already exist. For it to already exist the MSI must have been uninstalled but failed to remove the web site. Or another application is using the same web site name – which is based on the DT Application Name - and then IIS was uninstalled.
These seem rather unlikely circumstances.
If it does occur that IIS is uninstalled and there is an existing web site with the same name, then that web site is used by LANSA.
If IIS is already installed, the currently logged on user must be able to query IIS so that current web sites and ports, etc, may be enumerated. A non- administrator cannot query IIS therefore the MSI install will terminate, with a message saying to either logon as Administrator or open an administrative command prompt and run the MSI from there.
Uninstall may be run by administrator or non- administrator (provided administrator user id and password are known) for all types of installations, as IIS is not queried during the User Interface part of the MSI Install. IIS access only occurs with the process that is elevated and thus permission to administer IIS has been obtained. And an install does not necessarily need to be elevated and thus for those installs the administrator logon details are not required for a non- administrator user.
