Re: receiving broadcasts from host zero in a subnet?

Jens-Uwe Mager (jum@baghira.han.de)
Wed, 20 Oct 1999 15:12:45 +0200


On Wed, Oct 20, 1999 at 04:53:55AM +0200, Andi Kleen wrote:
> jum@ra.han.de (Jens-Uwe Mager) writes:
>
> > I am attempting port a program to linux that listens to broadcast UDP
> > packets from a particular device while performing a network boot. This
> > UDP broadcast is received OK if it is from the all zeroes 0.0.0.0 address
> > to the all ones broadcast address. But if the packet is from for example
> > 192.168.1.0 to 192.168.1.255 (with subnet mask 255.255.255.0) the packet
> > does not appear to be received on an UDP socket bound to INADDR_ANY. The
> > device in questions its subnet but not its IP address so it uses this
> > peculiar broadcast. Is there any special rule I need to enable to receive
> > these kind of broadcasts?
>
> SO_BROADCAST, as documented in socket(7).

This option is already turned on, otherwise I would not have been able
to send broadcast packets.

-- 
Jens-Uwe Mager	<pgp-mailto:62CFDB25>

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