What is needed on Mikrotik router config to enable UDP hole punching in NAT. E.g. which filter and NAT rules to set on firewall?
My setup is simple. I have Microtik 4G Router connected directly to Internet over mobile connection. I have public IP address on lte1 interface. I would like to test UDP hole punch mechanism from inside network.
Idea is this. With the help of STUN server which is located on public Internet like stun1.l.google.com first to know which is my public IP address and port after NAT translation.
This will be done with a help of stunc tool on my local machine which is connected directly to LAN side of router.
stunc stun1.l.google.com -b
assign_socket: local socket is bound to 0.0.0.0:54315
stunc_bind_cb: stun_discovery_done
stunc_bind_cb: local address NATed as PUBLIC IP:54042
Then will listen on local port with: ncat -ul 54315. After that I would like to pass command from inside LAN: echo "Test UDP hole punch" | ncat -u PUBLIC IP:54042.
As I understand the easiest way is to force FULL Cone NAT setup on router. But what exactly steps are needed? I am not concerned with security for now.