In the situation where you have a T1 hooked up to a router, then to an ISA Firewall enabled Server, then a switch, and then various servers & other pc's, what would happen if the ISA machine went down (i.e. pull the power plug). Do the servers and pc's still get internet traffic, or does the ISA server being down prevent any machines behind ISA from getting any internet traffic?
If the configuration is router ----> ISA ----> switch ----> other servers, etc. then if the ISA computer goes down, the network card loses power, and therefore cannot route packets back and forth any more.