The other day I ran across a piece of software configured to "multicast" using the address 255.5.6.7.
While I've seen local broadcast (255.255.255.255) and "true" multicast (as defined in rfc5771), this address seems to reside outside either of those recommendations. The address did seem to work, however, as a corresponding client was receiving the messages (it was on the same subnet).
I was wondering if this address worked merely since the first octet identified as broadcast, and network devices are coded to shortcut the logic. Does anyone know if this is the case or whether this address falls within another commonly recommended block?