Well, I created a gre tunnel in virtualbox connecting two linux vms, and it worked very well. But whenever I reboot the vms, the gre simply disappears. Is there any command I can use to save gre? Or, how do I write the gre tunnel to the Linux files so it stays saved?
Both vms are Debian 12
VM1 two adapters Bridged Network mode and VM2 one adapter Bridged Network mode
Commands:
VM1:
ifconfig enp0s3 down
ifconfig enp0s8 down
ifconfig enp0s3 A.B.C.Y/24 (PUBLIC IP Internet) up
ifconfig enp0s8 192.168.1.1/24 up
route add -net 192.168.1.0/24 enp0s8
route add default gw A.B.C.X (Gateway Internet)
echo 1 > /proc/sys/net/ipv4/ip_forward
iptunnel add vpn1 mode gre remote 192.168.1.2 local 192.168.1.1 key 123456
ifconfig vpn1 10.0.0.1/30 pointopoint 10.0.0.2
route add -net 192.168.2.0/24 gw 10.0.0.2
iptables -t nat -A POSTROUTING -o enp0s3 -j SNAT --to A.B.C.Y
VM2:
ifconfig enp0s3 down
ifconfig enp0s3 192.168.1.2/24 up
route add default gw 192.168.1.1
echo 1 > /proc/sys/net/ipv4/ip_forward
iptunnel add vpn1 mode gre remote 192.168.1.1 local 192.168.1.2 key 123456
ifconfig vpn1 10.0.0.2/30 pointopoint 10.0.0.1
