The tailscale client does this trick to force its way through NAT-to-NAT connections. "How NAT traversal works" - https://tailscale.com/blog/how-nat-traversal-

The tailscale client does this trick to force its way through NAT-to-NAT connections. "How NAT traversal works" - https://tailscale.com/blog/how-nat-traversal-works https://tailscale.com/blog/how-nat-traversal-works > "The benefits of birthdays"