I’ve always wondered why in some of my implementations of the ISA firewall that the log off process took so long. Now I have an answer in this KB article:
Clients take a long time to log off an OWA session after you publish an OWA server and configure OWA forms-based authentication in ISA Server 2004
at http://support.microsoft.com/default.aspx?scid=kb;en-us;920139&sd=rss&spid=2108#top
HTH,
Tom
Thomas W Shinder, M.D.
Site: www.isaserver.org
Blog: http://blogs.isaserver.org/shinder/
Book: http://tinyurl.com/3xqb7
MVP — ISA Firewalls