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> Hole punching refers to cooperative nat traversal, that is, with help from the inside - in every discussion I have ever seen. If by cooperative you mean that
by vetinari 8y ago
> Hole punching refers to cooperative nat traversal, that is, with help from the inside - in every discussion I have ever seen.
If by cooperative you mean that there is outcoming connection on the port, then yes, that's cooperative. If by cooperative you mean some sort of port mapping, whether manual or UPnP, then no, you don't need that.
For details, see the paper linked in sibling response.
- beagle3 8y agoThat paper does not support your assertion that "most NATs do not check the source address and only check the port", in fact, they only consider "endpoints" which are (ip,port) pairs. Thinking about it, any NAT that ignores the ip part is horribly broken. I still await your examples of routers in actual use that have this behaviour.