[VPN] NAT-T and private addressing

[Stephen J. Bevan]

David Newman writes:
 > We are contemplating renumbering here (gack) but we also want to maintain
 > IPSec connectivity with a customer site that uses net-10 addressing.
 > 
 > Even if two IPSec boxes support NAT-T, is it the case that we cannot use the
 > same address space for the two private networks? (eg, a VPN client on our
 > private 10.0.0.0/24 cannot reach a box on the customer's 10.0.0.0/24, even
 > if the public interface of one gateway is a public address)?

A very similar question was posed in :-

  <http://sisyphus.iocaine.com/pipermail/vpn/2002-July/003462.html>

The short answer is that is possible to do it though it depends on
your hardware/software.  See the followups to the above for more
details.