Subject: PPP and multicast bits
To: None <tech-net@NetBSD.ORG>
From: Michael Richardson <>
List: tech-net
Date: 01/28/1996 20:03:56
  [my appologies if this is the wrong list for this. Please redirect
me. I've just re-subscribed to a bunch of netbsd lists after a hiatus,
to find a whole bunch of new lists... I have yet to see any traffic
from tech-net..]

  Under NetBSD 1.1 the sl? interfaces come up with the MULTICAST bit
set on them. The PPP interfaces do not.
  I'd like to be able to do RIPv2 out my PPP interface(s) since I need
to advertise my /28 subnet that I use at home. 
  I hacked the IFF_MULTICAST bit and a clause into pppsioctl to handle
the SIOCADDMULTI, SIOCDELMULTI. I stole the code out of net/if_sl.c
  Well, I don't think gated is able to do the right thing yet anyway.
I suspect the gated code is still being conservative... The gated (3.5B3)
manual says:
   RIP-II and OSPF specify the use of IP multicast on P2P interfaces. Due to bugs in most
   implementations of the IP multicast code GateD will not be able to specify it's use on these
   interfaces. GateD will automatically fall back to using the destination address of the P2P
   link. In the OSPF case, no functionality will be lost, but in the RIP-II case you will loose
   the ability to pass arbitrary subnet masks via these interfaces. 

  I used the NetBSD1.0A-Sparc config file as a basis when I built.
Does NetBSD still have this bug? Does anyone know what this bug is? I
asked this once on the gated-people list, but got silence. I'll ask it
again tomorrow from work (where I read gated-people).

   Another bug in IP multicast support causes multicast packets to local-wire groups to fail if
   there is not a default route for IP, multicast, or the specific group. As a workaround, GateD
   installs a default route for any local-wire multicast group it uses via the loopback interface.
   This default is not actually used, but it avoids a kernel bug sending to these groups. 

  Is this bug still present in NetBSD, or not?


   :!mcr!:            |  "Elegant and extremely rapid for calculation are the 
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