Hi Peter:



> 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);
>

Actually you can do this by add more than one -P on the command line. You may already know this.
 
> 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.
> 

As noted in an email I just sent you, this was added to dhclient for 4.4.0.  However you cannot set it individually per interface.  One value for all.

Regards,

Thomas Markwalder
ISC Softare Engineering



> 	-hpa
>