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You just send a (UDP) packet to the other side's address and port and they send one to yours. The firewalls treat it as an outbound connection on both sides.
by immibis 1y ago
You just send a (UDP) packet to the other side's address and port and they send one to yours. The firewalls treat it as an outbound connection on both sides.
- mightyham 1y agoI don't believe that's true. You would still need something like UDP hole punching to bootstrap the inbound flow on both sides first. Also you would still only be limited to UDP traffic, TCP would still be blocked.
- immibis 1y agoSending one packet outbound is hole punching. It's really that simple. Since there's no NAT, you don't need to bother with all the complexity of trying to predict the port number on the public side of the NAT. You just have two sides send at least one packet to each other, and that opens the firewalls on both sides.
- GoblinSlayer 1y agoYou just need to tell the other side that you want to connect.