>> All of these applications depends on the "MROUTING" kernel option, >> it seems, which is mostly default-off, except for a few (tending >> on the more obscure side) kernel configs. I wonder if anyone >> knows the history there. > > I'm not really sure why MROUTING is default off [...]
Isn't MROUTING the kernel support to act as a multicast router, typically by using the DVMRP protocol, implemented in mrouted. People operating multicast networks today typically do that using real routers and variants of PIM. I don't think NetBSD ever got the ability to do PIM, nor IGMP3 for that matter, I vaguely seem to recall there being licensing issues involved, at least for the latter. Typically, MROUTING isn't needed to *use* most of the non- routing-focused multicast-based tools, e.g. I run a dbeacon instance with just a normal GENERIC kernel using any-source PIM. Regards, - HÃ¥vard