From owner-freebsd-small  Wed Apr 25 13:15: 4 2001
Delivered-To: freebsd-small@freebsd.org
Received: from rgmail.regenstrief.org (rgmail.regenstrief.org [134.68.31.197])
	by hub.freebsd.org (Postfix) with ESMTP
	id 33AD737B424; Wed, 25 Apr 2001 13:14:58 -0700 (PDT)
	(envelope-from gunther@aurora.regenstrief.org)
Received: from aurora.regenstrief.org (rgnout.regenstrief.org [134.68.31.38])
	by rgmail.regenstrief.org (8.11.0/8.8.7) with ESMTP id f3PKFCA32650;
	Wed, 25 Apr 2001 15:15:12 -0500
Message-ID: <3AE7303F.957DE6DC@aurora.regenstrief.org>
Date: Wed, 25 Apr 2001 20:14:55 +0000
From: Gunther Schadow <gunther@aurora.regenstrief.org>
Organization: Regenstrief Institute for Health Care
X-Mailer: Mozilla 4.75 [en] (Win98; U)
X-Accept-Language: en
MIME-Version: 1.0
To: freebsd-net@freebsd.org, freebsd-small@freebsd.org,
	snap-users@kame.net
Subject: VPN tunnel with DHCP ...
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Sender: owner-freebsd-small@FreeBSD.ORG
Precedence: bulk
X-Loop: FreeBSD.ORG

Hi,

about my SOHO router project, I came accross a tough problem, may
be I overlook that there is a solution already? The VPN gateway
at the small office / home office (SOHO) has an IPsec tunnel 
connecting it to its headquarter:

setkey -c  <<END
  spdadd ${sohonet} ${homenet} -P out ipsec
     esp/tunnel/${sohoip}-${homeip}/require;
  spdadd ${homenet} ${sohonet} -P in ipsec
     esp/tunnel/${homeip}-${sohoip}/require;
END

now, the problem is that the ${sohoip} is dynamically assigned 
with DHCP. How can the gateway at the headquarter know that 
${sohoip} address?

Options I can see are:

A DNS (provided that the SOHO endpoint has a reliable name assigned
  by the ISP ... doesn't work for intermittent/dialup lines.)

B an authenticated message from the SOHO endpoint to headquarter
  stating that the network ${sohonet} is reachable through the 
  tunnel with endpoint ${sohoip}.

Is there anything like B defined in IPsec / ISAKMP or something?

regards
-Gunther

-- 
Gunther Schadow, M.D., Ph.D.                    gschadow@regenstrief.org
Medical Information Scientist      Regenstrief Institute for Health Care
Adjunct Assistent Professor        Indiana University School of Medicine
tel:1(317)630-7960                         http://aurora.regenstrief.org

To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-small" in the body of the message