I used “local address” properties in EoIP tunnel configuration, and now in my firewall, I can see a GRE connection from 120.79.186.223->73.238.75.222.
However, this change only affects the header of GRE packet, and it will still go to the default route. The default gatway doesn’t know who is 120.79.186.223, so packet can’t arrive.
Then, I tried to use Mangle rule on output chain to mark the routing. And add a routing mark on 120.79.186.223 reachable. Again, I am still able to see the connection 120.79.186.223->73.238.75.222 from the firewall and packet sniffer. But it still does not arrive. And I can’t see the connection from the other side.
I checked these topics:
http://forum.mikrotik.com/t/how-to-mark-packets-going-from-router-itself/85965/1
http://forum.mikrotik.com/t/routing-mark-on-output-chain-not-working-solved/20146/1
http://forum.mikrotik.com/t/matching-traffic-from-the-router-itself-in-mangle/91224/1
http://forum.mikrotik.com/t/the-output-chain-and-vrfs-routing-marks/102125/1
Still didn’t solve my problem. Any idea would be helpful. Thanks!