[Openswan Users] HOWTO configure multi-site VPNs

[John Mok]

Hi,

Due to link speed of regional internet connection, I need to setup 
Openswan VPN to link multiple sites in a straight line rather than fully 
meshed manner :-

     subnet 1        subnet 2         subnet 3
192.168.1.0/24   192.168.2.0/24   192.168.3.0/24
       GW1--------------GW2--------------GW3
   (211.1.1.1)      (61.1.1.1)       (210.1.1.1)

The VPN connections between subnet1-subnet2 and subnet2-subnet3 work 
fine, but I can not ping between subnet1-sbunet3. I added the routings 
to both subnet 1 and subnet 3, e.g. ip route add 192.168.3.0/24 dev 
ipsec0, but it still does work.

Can anyone help to advise me how to configure the VPN connections such 
that subnet 1 can reach subnet 3 via subnet 2?

Thanks a lot.

John Mok