ISA Firewall 2006 Site to Site VPNs Allow FQDNs when defining the Remote Site Gateway. This is a big improvement over ISA 2004, where you could only use an IP address to define the Remote Site Gateway. The reason for this is that branch offices often use connections that force them to use dynamic addresses. This is no longer a problem with the new ISA firewall, as you can see in the figure below.
Thomas W Shinder, M.D.
MVP -- ISA Firewalls