IANA supplies criteria on this issue. For IPv4, here is what they may have inside their "Particular reason deal with registry". Meaning, for our uses, something in these tackle blocks shouldn't be assigned because they should not be routable "publicly". Number945Number945 61711 gold badge55 silver badges99 bronze badges one 1 https://judahvgscr.bleepblogs.com/37101187/255-payday-loan-can-be-fun-for-anyone