Windows Longhorn Server introduces major changes which have the potential to affect Server Applications produced by our ISVs:

Impact of the Windows Firewall ON by default:

As of Beta 3, LH Server has a symbiotic relationship with the Windows Firewall: LH Server Beta 3 is the very first Windows Server release to have the firewall ON by default. This represents a major change from Windows Server 2003 SP1 where the Windows Firewall was only turned ON by default on new installations while the OS was being configured and updated. To make sure that LH Server Roles and Optional Components work out of the box with the Windows Firewall ON by default, they have been updated to manage the Windows Firewall automatically. However most third-party Server applications will not be aware of this change in the firewall behavior and will break.

To mitigate the impact, we have created a Best Practices document designed to guide ISVs through the process of integrating their Server Applications with the Windows Firewall APIs (see attachment).

Impact of the new networking stack:

The Windows networking stack has been completely re-written for Vista and Longhorn and the new features that may pose potential compatibility issues include:

These features are described here:

http://www.microsoft.com/technet/community/columns/cableguy/cg0905.mspx

http://www.microsoft.com/technet/community/columns/cableguy/cg1105.mspx

http://msdn2.microsoft.com/en-us/library/Aa480152.aspx#appcomp_topic13

If you want to receive the "Windows Firewall best practices for rule authoring and API usage" document for ISV , send me an email at

mailto:philippb@microsoft.com

Philippe