Gre tunnel linux cisco

• LINUX WAN IP = 192.168.240.252
• CISCO WAN IP = 192.168.244.96

Linux Site

• ip tunnel add gretun mode gre remote 192.168.244.96 local 192.168.240.252 ttl 255
• ip address add dev gretun 10.11.12.13/24
• ip link set gretun up

Cisco Site

interface Tunnel1
 ip address 10.11.12.12 255.255.255.0
 ip mtu 1400
 ip tcp adjust-mss 1360
 tunnel source 192.168.244.96
 tunnel destination 192.168.240.252

• https://learningnetwork.cisco.com/docs/DOC-2457