http://blogs.technet.com/yuridiogenes/archive/2008/07/30/do-you-really-know-what-is-and-what-is-not-supported-on-isa-server.aspxLast two months for some reason were pretty busy of calls for ISA Server issues where customers were running on a non supported scenario. Interesting enough, the articles for non supported configurations are out there since ISA Server 2004. Maybe it isen-USCommunityServer 2.1 SP1 (Build: 61025.2)