>I think I get the picture: two internal subnets and ISA is used as router > between them. In effect yes! Used to join the two networks together and internet routing > Can all hosts on subnet2 not ping hosts on subnet1 or only some? Just checked again subnet2 can only ping the ISA Server on subnet1. > Are there any further subnets behind the ISA? Nope only the ones listed > Do all hosts in subnet2 have a route to subnet1, either by default gateway > or specific route? Subnet2 get a default gateway of ISA Server for its subnet 192.168.2.1 (not the real address but you get the picture) > It seems to me it is a pure routing problem, not related to ISA. Exactly my thoughts but I can't seem to fix the thing tried lots of little bits. Kind Regards, Chris Bond