On Mon, May 24, 2010 at 12:48, Wietse Venema <wie...@porcupine.org> wrote:
> 0.0.0.25 is not a valid IPv4 address. It is a valid way to express the last 32 bits of any IPv6 address. It only needs to be a valid IPv4 address if the previous 96 bits are "::ffff" (or one other case I don't reacall that I read about). It is used, for example, to map the chosen host-part of the IP address onto network prefixes. For example, when using the last 16 bits as a host part, the IPv4 prefix would be 16 bits while the IPv6 prefix would be 112 bits. But this isn't the first case I have to revert to the pure hex form.
