User:Clandmeter

We start by adding mGRE tunnels to our network configuration. In conjunction with IPsec VPNs this allows passing of routing information between connected networks.

auto gre1
iface gre1 inet static
       pre-up ip tunnel add $IFACE mode gre key 42 ttl 64 dev br0 || true
       address 192.168.148.2
       netmask 255.255.255.255
       post-down ip tunnel del $IFACE || true

The vici plugin provides VICI, the Versatile IKE Configuration Interface. As its name indicates, it provides an interface for external applications to not only configure, but also to control and monitor the IKE daemon charon.

My notes on DMVPN

ip tunnel add gre1 mode gre remote 172.16.4.1 local 172.16.3.1 ttl 255
ip link set gre1 up
ip addr add 192.168.148.1/24 dev gre1

ip tunnel add gre1 mode gre remote 172.16.3.1 local 172.16.4.1 ttl 255
ip link set gre1 up
ip addr add 192.168.148.2/24 dev gre1