It would be very nice to add support in dhclient for:

a. requesting more than one IA_PD prefix; a router may want to request
one for each downstream interface (as it seems consumer ISPs at least
are planning to hand out /64's);

b. sending a prefix length hint (an IA_PREFIX option with a prefix
length but all other information zero) to the server to hint at the
prefix length desired.

	-hpa