[Openswan Users] How to combine two VPN tunnels

[Paul Wouters]

On Mon, 13 Apr 2009, Curu Wong wrote:

>    I am in such a situation of VPN configuration:
>   gateway gwA with a fixed public IP,And there is a subnet
> 192.168.9.0/24 behind it.
>   gateway gwB,which obtains its IP from ISP using pppoe,And there is
> a subnet 192.168.30.0/24 behind it.
>   There is a tunnel between the two subnets via gwA and gwB.And there
> is a tunnel for road warrior to connect subnet 192.168.9.0/24 via gwA.
>   What I want is to connect to both subnets
> (192.168.30.0/24,192.168.9.0/24) as a road warrior via gwA, Is this
> possible?
>    By the way,I don't want to use l2tp.

You cannot, since subnetB or gwB would need to "know" where the
roadwarrior is to ensure its packets for subnetB would get send
via the tunnel to gwA. But since roadwarrior is on a dynamic IP,
you cannot know.

Unless you route all non-local traffic for subnetB via a tunnel
to gwA.

Paul