There is no "official" description of a NAT based trihomed DMZ config. However, it can be done with a little elbow grease and ingenuity. I go over those scenarios in the ISA Server and Beyond book. I like others are awaiting the printing and distribution. I just hope Amazon does not decided to lose the order I place well over a month ago. Of course, if you want to send me a signed copy. Also, you never read my stuff anymore :( Check out: LOL. Guilty as charged. (Of course, the fact that I have been concentrating on tri-homed scenarios does not count.) BTW, I didn't know there are two of you: Dr. Tom Shinder's Isa Server and Beyond: Real World Security Solutions for Microsoft Enterprise Networks by Thomas <http://www.amazon.com/exec/obidos/search-handle-url/index=books&field-autho r=Shinder%2C%20Thomas%20W.%2C%20Dr./002-3846481-6692817> W., Dr. Shinder, Martin <http://www.amazon.com/exec/obidos/search-handle-url/index=books&field-autho r=Grasdal%2C%20Martin/002-3846481-6692817> Grasdal, Debra <http://www.amazon.com/exec/obidos/search-handle-url/index=books&field-autho r=Shinder%2C%20Debra%20Littlejohn/002-3846481-6692817> Littlejohn Shinder, Tom <http://www.amazon.com/exec/obidos/search-handle-url/index=books&field-autho r=Shinder%2C%20Tom/002-3846481-6692817> Shinder And they can't even spell ISA server correctly. John Tolmachoff MCSE, CSSA IT Manager, Network Engineer RelianceSoft, Inc. La Habra, CA 90631 www.reliancesoft.com