Isakmpd and dynamic IPs configuration?

["Thierry TM. Michalowski" <Thierry.Michalowski@echotech.ch>]

Hi,

I would like to use OpenBSD boxes to create an IPSec VPN in the
following way:

192.168.10.x --Box A (IP1) ---------- (IP2) Box B -- 192.168.11.x
                     |------------------------------------ (IP3) Box C
-- 192.168.12.x

I'm using X509 certificates to authorize connections, and the various
firewalls have port 500 open to the world.

When Box A,B,C have a static IP address I managed to create the VPN
tunnels.
However, that required me to create my peers and connections in
isakmpd.conf by assigning an explicit IP address for each of them.

Now, what I would like to do is that Box A and Box B have a
dynamically-assigned IP address.
How should I do this with isakmpd?
(I'm using OpenBSD 3.2).

Best regards,
Thierry Michalowski