I've noticed through watching Wireshark that when an iPhone connects to a wifi network, it sends out a few IGMP/MDNS packets to 224.0.0.251 (LAN broadcast, I think). Is there any easy way to watch for these packets and then either run a script or send an event?

Or, is the best way to just run a packet sniffer? Any simple ones that can send events or execute curl commands when a filter is triggered?

When I run nc -u -l 5353 I get:

My-Name-iPhonelocal???
                            x???)??
                                  ??cc^C

Can I do something like: nc -u -l 5353 | grep iPhonelocal | execute command...