MicrosoftApologies if I am unclear. This is not an area that I understand the correct terminology. For me, it is just an incoming packet that might come from any source. I am not convinced it matters whether it is multicast or not in my scenario. All I am saying is that there are multiple processes with the same UDP port open. How does the traffic know where to go? I assume it is based on source port, but what if the source ports are the same? Are you saying that, because it is mDNS, it will be delivered to all? If so, how could one allow\block it with a firewall rule for one process and not the others? I am not convinced you can. I suspect I am missing the whole point here.......
See my machine below. I have three processes listening on port UDP5353
C:\WINDOWS\system32>netstat -aon|findstr 5353
UDP 0.0.0.0:5353 *:* 17472
UDP 0.0.0.0:5353 *:* 1120
UDP 0.0.0.0:5353 *:* 1924
UDP 0.0.0.0:5353 *:* 1120
UDP 0.0.0.0:5353 *:* 1120
UDP 0.0.0.0:5353 *:* 17472
UDP 0.0.0.0:5353 *:* 17472
UDP [::]:5353 *:* 1924...this is svchost.exe
UDP [::]:5353 *:* 1120...this is chrome.exe
UDP [::]:5353 *:* 17472...this is msedge.exe
