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I have 4 machines
machine 1 have ip address 172.13.0.40/24 machine 2 have two ip address 172.13.0.1/24 and 172.12.0.1/24 machine 3 have two ip address 172.12.0.50/24 and 172.17.0.1/24 machine 4 have ip address 172.17.0.30/24
machine 2 and 3 have NAT on both ways
we can ping from machine machine 1 to machine 4 and vice versa
I need a tunnel 10.0.0.0/25 to be formed between machine 1 and 4
I used following commands
ip tunnel add gtt0001 mode gre remote 172.13.0.40 local 172.17.0.30 ttl 255 dev eth1
ip link set gtt0001 up
ip addr add 10.0.0.0/24 broadcast 10.0.0.255 dev gtt0001
ip link set gtt0001 multicast on
ifconfig gtt0001 10.0.0.21 netmask 255.255.255.0
ip route add 172.13.0.0/24 dev gtt0001
similar commands on machine 4
But I cannot ping 10.0.0.21 from machine 4 and vice versa