Hi. I have a test network. I can’t figure out how to wrap traffic in the gre tunnel on vm3. so with vm1 you can reach vm4.
My iptables config on vm2:
echo 1 > /proc/sys/net/ipv4/ip_forward && sudo iptables -t nat -A POSTROUTING -j ACCEPT
vm1:
sudo ip tunnel add gre1 mode gre local 10.0.0.2 remote 10.0.1.2 ttl 255
sudo ip link set gre1 up
sudo ip addr add 10.20.30.1/30 dev gre1
sudo ip route add 10.0.1.0/24 via 10.0.0.1
sudo ip route add 10.0.5.0/24 via 10.20.30.2
vm3:
sudo ip tunnel add gre1 mode gre local 10.0.1.2 remote 10.0.0.2 ttl 255
sudo ip link set gre1 up
sudo ip addr add 10.20.30.2/30 dev gre1
sudo ip route add 10.0.0.0/24 via 10.0.1.1
sudo iptables -t nat -A POSTROUTING -o eth2 -j MASQUERADE
sudo iptables -A FORWARD -i gre1 -o eth2 -j ACCEPT
iptables everywhere everything is open. nothing is blocked