Cisco IOS gre over ipsec config example

crypto isakmp policy 10
encryption aes 256
hash sha
authentication pre-share
group 2
lifetime 3600

crypto isakmp key 1 MySecretKey address 10.0.0.2

crypto ipsec transform-set MyTS esp-aes 256 esp-sha-hmac
mode tunnel

crypto ipsec profile MyProfile
set transform-set MyTS

interface Tunnel0
ip address 172.16.0.1 255.255.255.252
tunnel source 10.0.0.1
tunnel destination 10.0.0.2
tunnel mode ipsec ipv4
tunnel protection ipsec profile MyProfile