>It seems that the problem is in prelist_update in file nd6_rtr.c. The handling 
>of vltime is a bit buggy at least to my understanding of what the RFC 2462 is 
>specifying in together with the discussion in the ipngwg. 
>
>The major fault that I noticed was that the code compares the vltime received 
>in the earlier RA to the vltime received in new RA, when the vltime is 
>smaller than 2 shours and makes the update decission based on that. Now if 
>the new vltime is same as the previous or smaller no update to the valid life 
>time will be done and that causes that the address is lost always when the 
>valid life time expires. Here is a patch file that will patch the code in the 
>way I believe it should work. This changes the behaviour so that the vltime 
>is compared in to the remaining lifetime of the address instead of the the 
>whole life time. At least after making this correction I got work in all my 
>test cases.

	thanks for catching this.  it was corrected in KAME repository
	as well as netbsd-current.  i didn't request pullup to 1.6 (it's a
	large change so it may not be suitable, i thought) so that's why you
	are seeing the problem.  if possible try using netbsd-current.
	i'll look at your patch and may request pullup for 1.6.2.

itojun