On Wed, Dec 29, 2010 at 9:52 PM, David F. Skoll <d...@roaringpenguin.com> wrote:
>> and shared hosting providers may >> allocate smaller ranges to their customers (why not an individual IP >> to each customer?). > > Because then your routing table gets insane. They may allocate the IPs in a virtualisation layer. > If dnswl.org and others announced that (1) they would whitelist only > to the granularity of a /64 and (2) any providers that put different > customers in the same /64 would be ineligible for whitelisting, > economics would quickly move providers to allocating at least a /64 to > each customer. Today, querying IPv4 DNSxLs is more or less limited to individual IPs. Making a new protocol that has more flexibility is very much needed - one size will not fit all, especially not in the protocol design. > http://tools.ietf.org/html/rfc3177 allows for assignment of a /128, > but only under quite restricted circumstances. See "3. Address > Delegation Recommendations" in that RFC. (Yes, it's only informational, > but it should still carry a fair amount of weight.) And it argues to assign /48s to end-user systems, which does not seem to be a very well established practice today. -- Matthias
