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Re: simultaneous lifetime type support required?
Michael C. Richardson writes:
> >>>>> "Scott" == Scott G Kelly <skelly@redcreek.com> writes:
> Scott> others, it is appropriate to support it. But DOI only refers to phase 2,
> Scott> so what about phase 1? Is there language anywhere defining this?
> Frankly, I don't think that the ISAKMP SA will pass enough bytes to
> ever justify expiring it by byte count. Time will always be the critical
> factor for expiring keys for ISAKMP.
> [If I'm wrong, and that the ISAKMP will pass megabytes of data in
> under a hour or two, then there is probably something very wrong..]
I agree, that you propably don't transfer that much data that it would
make it easier to break the encryption of phase 1 sa, but you can also
use the kilobyte lifetime to limit how many phase 2 negotiations can
be negotiated using that phase 1 sa.
If you are using pre shared keys and normal ip identities and simple
proposal then one phase 2 negotiation will take about 250 bytes in
each directions if you use PFS, and 150 bytes if you don't use pfs, so
if you set the kilobyte limit to 10 kilobytes that means about 40
phase 2 negotiations using PFS or 70 phase 2 negotiations without PFS,
inside that phase 1 negotiation.
I would also like to have phase 1 lifetime that could be used to limit
number of negotiations done under that phase 1 sa (now the draft says
it is local policy issue, but I would also like to tell/negotiate that
to the the remote end also). But it already too late for that, but
perhaps in the ipsecond.
--
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