Today I was asked an odd question about the use of IP subnet zero in theory. Since I am not the expert on the material and haven't memorized the RFC I figured I would ask everyone.
Is this ever possible?
0.1.2.3 as a host address
Yes that should be possible. This is a class 'A'address. Remember class is between 0 - 127. But we don't take 0.0.0.0 because we use that address to give a default route. 127 network also we don't use because 127 range is for testing, eg: 127.0.0.1 loopback address.
Therefore theoratically this should work.