Subnet to subnet VPN

Building a tunnel between two endpoints for multiple subnets is pretty simialar to a host to host VPN tunnel. Except you will see we are adding leftsubnets/rightsubnets statements. We used the also= keyword to avoid adding the same information into each connection.

# /etc/ipsec.conf
# The version 2 is only required for compatibility with openswan
version 2

config setup
    protostack=netkey

conn mysubnet
     also=mytunnel
     leftsubnet=192.0.1.0/24
     rightsubnet=192.0.2.0/24
     auto=start

conn mysubnet6
     also=mytunnel
     connaddrfamily=ipv6
     leftsubnet=2001:db8:0:1::/64
     rightsubnet=2001:db8:0:2::/64
     auto=start

conn mytunnel
    leftid=@west
    left=192.1.2.23
    leftrsasigkey=0sAQOrlo+hOafUZDlCQmXFrje/oZm [...] W2n417C/4urYHQkCvuIQ==
    rightid=@east
    right=192.1.2.45
    rightrsasigkey=0sAQO3fwC6nSSGgt64DWiYZzuHbc4 [...] D/v8t5YTQ==
    authby=rsasig
    # use auto=start when done testing the tunnel