e38BimmerFN
Very Senior Member
Yes I believe that some newer routers only have this Symmetric NAT support in there FW. While some of the older generation routers I have, they have the ability to select and use the Full Cone NAT configuration which is why I'm seeing OPEN NAT across the board with these routers vs newer generation routers, except for the NetGear R7800 which is fairly new and I can get OPEN NAT across the board with two consoles playing the same game, i.e. BO3.
Full Cone NAT is one where all requests from the same internal IP address and port are mapped to the same external IP address and port. Furthermore, any external host can send a packet to the internal host, by sending a packet to the mapped external address.
Symmetric NAT is one where all requests from the same internal IP address and port, to a specific destination IP address and port, are mapped to the same external IP address and port. If the same host sends a packet with the same source address and port, but to a different destination, a different mapping is used. Furthermore, only the external host that receives a packet can send a UDP packet back to the internal host.