[KLUG Members] multicast

[Adam Williams]

> http://www.tldp.org/HOWTO/Multicast-HOWTO.html
> (Frankly, the whole multicast thing, as an Internet-wide phenomenom,
> seems less than half-baked.)

OSPF (the Internet routing protocol) uses multicast, so it must work. :)

But I agree, you should only need multicast if you REALLY need
multicast.  But he has a brain-dead application that uses
multi-casting.  Good or bad, I understand the situtation of having
application ABC and just having to make the @*@($%& @@#$*$*@
$&@*$&&*!!!!! thing work.

> I think I understand that this Linux box is a dedicated firewall
> connecting 4 network segments. As such, this box doesn't seem to require
> the ability to send its own multicast packets, correct?

No, it need to pass them on.

> Also, are these four segments all internal networks, or do you have
> three internal segments and one external Internet gateway? I think
> Adam's suggestion, of using transparent bridging, the best. Whereas the

I'm not certain the bridging idea will work,  but it is worth a shot.  
I know that some OSPF implementations (which uses mutlicast where
possible) have bridging hidden somewhere in their guts.

> rule for an external firewall is to DROP everything and then punch
> necessary holes in it, for an internal network a bridge should ACCEPT
> everything by default except for any DROPs you then add.

I don't know,  I have bridges that reject by default, it really depends
what your trying to accomplish.  Really, bridging in Linux isn't so much
making "a bridge" (in the orthodox sense) but creating an intellegently
aggregated collection of interfaces.