mDNS
Packet structure
https://en.wikipedia.org/wiki/Multicast_DNS
An mDNS message is a multicast UDP packet sent using the following addressing:
IPv4 address 224.0.0.251 or IPv6 address ff02::fb
UDP port 5353
When using Ethernet frames, the standard IP multicast MAC address 01:00:5E:00:00:FB (for IPv4) or 33:33:00:00:00:FB (for IPv6)