>>>>I have NetBSD 1.6.1RC3 installed and I noticed following behaviour in
>>>> autoconfiguration. The autoconfigured addresses dissapears every
>>>> once and a while for a few seconds. What I noticed was that this
>>>> happens every time the address has been configured for a valid life
>>>> time
>>>>although the host has received a number of router advertisements
>>>> during
>>>> this time.
>>>
>>> 	the basic suggestion is, as documented in rtadvd(8), do not have
>>> rtadvd.conf and let rtadvd(8) determine what prefix to be advertised
>>> from interface configuration in the kernel.  use rtadvd.conf only
>>> when you are sure really about it.
>>
>>But if I'll remove the prefix from the rtadvd.conf then the rtadvd will
>> advertise the prefix with it default valid life time and with default
>> preferred life time which are 2592000 and 604800 seconds although I
>> still have a valid life time of 60 seconds and preferred life time of
>> 30 seconds in the rtadvd.conf. That's why I have defined the prefix in
>> the
>>rtadvd.conf in order to be able to change the valid and preferred life
>> time of the prefix.
>
> 	ok.  but the values you have chosen are way too short.  i don'
> 	recommend such a setting.

Yes, I know that those are very short and not to be used in the normal
case but these values were chosen to demonstrate the problem because the
problem also exists if I have a longer life time for the addresses. All
the active connections will get no route to host while the address is
missing from the interface.

It is also quite irritating if one makes a program that listen's to
routing socket when you'll get all the time RTM_DELADDR and RTM_NEWADDR
from the routing socket because the address is lost and right after
reconfigured again. This causes waste of clock cycles which are used to
update all sort of neat routing stuff and few seconds later again updating
the same data back in.

   Jan