> That's not a multicast address; it's an (unusable) class-E 240/4 address. > > Weird to see traffic to it... > > Maybe someone has some bad glue? That's entirely possible. These servers are handling queries from thousands of servers and I'm sure that some domains have bad records. Each server has interface tracking set to automatic and the anycast IPs are on loopback interfaces. The messages don't seem to be causing any problems but I'd like to figure out what's causing them.