Multicasting to 127.0.0.1 on Solaris 8
This well known bug was that no packet is recieved. This is fixed by one of the Recommended Patches (108528), which is applied to my system and sovles the problem as described in Bug Suns bug parade, id = 4377103.
But it still is not fixed with two recievers, only one will get the package. This is the same with jdk 1.5. I filed a bug report.