CCNA, CCDA, CCNP, CCDP, CCIP, CCVP and CCIE
Hi Dave,I can understand your situation.Well, it's like this. Generally it says Class A range is 0 - 127. BUT 127.0.0.0 network has been reserved for testing perpurse. 0.0.0.0 is DEFINITELY INVALID as it is been taken to define the default route (gateway of the last resort). Considering these things, I don't see any problem in taking the IP address you have given as a valid host. Theoritically it should be a valid host address. But the best thing for you to do is, if you have a router, just configure that and see, (without ip subnet-zero command) if the router accepts it. If you have to give the command "ip subnet-zero" to configure that ip address, then it is not valid, at least according to Cisco.All the best!Omal.