Known issue with Infrastructure Update for Windows SharePoint Services 3.0
If you are planning to deploy this update to your production environment, pay attention to a known issue that may affect AAM functionality in which discovered after release of Infrastructure Update for WSS 3.0, the KB 951695 has been recently updated with more information on the issue:
"Installing the Infrastructure Update in a SharePoint farm that uses Alternate Access Mapping with a reverse proxy or a network load balancer, such as in an extranet deployment, may cause some public URLs to become unresponsive.
Microsoft is aware of this issue and is developing a solution. Before installing the Infrastructure Update, customers who use this configuration should use a test environment to verify that public URLs remain accessible after the update is installed."
