Well I mean, you're correct it would break the communication over NAT, but it breaks the communication over the local network at well. You might still receive t

Well I mean, you're correct it would break the communication over NAT, but it breaks the communication over the local network at well. You might still receive that packet to your NIC, but unless you know beforehand it will send using that source port and thus tell the OS (by setting up a socket or etc. to collect that packet) then the packet will never be routed to your application. So I don't really feel like this could be intended because it just makes stuff not work.