>> the last octet in ipv4, it is usually zero as a /24 is assigned. if >> you mean the last octet in ipv6, it also is usually zero, in fact >> the whole last 64+ bits are. > I read the above as saying "the last tuple of the network portion", rather > than of the whole 32/128 bits... So wouldn't that make it clearer? in post-cidr v4, what's a 'network portion'? similarly in v6, is it the rightmost 8 or 16 bits of the left 64? randy