I understand that ISA 2006 has an integrated Network Load Balancing feature. We also recently acquired a second internet line through a second service provider. I know it is possible to purchase a NLB router for using both incoming lines but this is not the route we would like to take if at all possible.
Thus, is it possible to have two ISA 2006 servers each with there own external connection, Load balanced to be viewed as one gateway? My thought was to have two ISA servers each with three NICs, one external, one internal and one for cross communication. I am under the impression that this should work but was hoping someone else has had experience with it.
ISP Load Balancing with ISA 2006
isa-servernetworkingnlbwide-area-network
Best Answer
For outgoing connections, this will work, although you might want to mess with the balancing setup if the outside lines are not the same bandwidth. However, Threat Management Gateway (next gen ISA replacement) includes real load-balancing on the outside, meaning one server could handle both outside lines and balance them, instead of having the inside balancing through NLB. That might be a better option for you.
see also isaserver.org.