[QUOTE=himitsu;1534562]
weiß nur grade nicht wie.
Fair question, and right on point, and yes if UDP as we know it from popular resources can't pass the packets inward from the Internet to specific NAT devices then how on earth QUICK and HTTP3 is working !??
and How my android with 4G connection with no real/Static
IP is connected to my router using WireGuard ?
And the answer is Stateful Packet Inspection, there is many pages explain it better than me with better language, but to be consistent with myself i will explain it in few words.
It is a technology that implemented in everywhere and no one specifically being notified, but not for the bad reasons on contrary it will give the routers and switches nice features, like in case with UDP if a packet went from specific local (NAT) address and port X:p to Y:r then anything UDP from Y:r to the router will be forwarded to that specific local X:p, without explicitly using UPNP or manually configure the router for port forwarding.
So in your case you can do it but remember there is no standard for this forwarding, this means there is no specific Time-To-Live (TTL) for such unspoken and hidden port forwarding rule, meaning your client should keep pinging the server at some T intervals, thus you server can send UDP packet to it as answers, find T on your own, i know T=30 is absolutely working everywhere, but 5 minutes should be fine too, again it is not standardized.