Granted, 0.0.0.0 is technically a valid IP address in some situations, as in dealing with network routes, but for most situations it would be considered as something out of the ordinary, which is why I initially mentioned it.

Also, leading zeros, while also technically valid, are also usually not what one would consider a proper IP address.

If you say ping 065.1.01.002, you are probably not going to ping what you think you are pinging.
(at least if you are trying to ping 65.1.1.2).

As you rightly said though, this is all a matter of context.:-). You must know your data before trying to implement any solution.

While using a regex for mild IP sanity checking may be ok in some situations,
I do agree though that as a rule, regexes should NOT be used parse IP addresses, as ybiC's excelent article states.

Best Regards,
Wonko