Messages in this thread | | | Date | Wed, 20 Oct 1999 21:47:05 +0200 | From | Jens-Uwe Mager <> | Subject | Re: receiving broadcasts from host zero in a subnet? |
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On Wed, Oct 20, 1999 at 03:30:18PM +0200, Andi Kleen wrote: > On Wed, Oct 20, 1999 at 03:12:45PM +0200, Jens-Uwe Mager wrote: > > 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. > > You need correct routing tables so that Linux knows that 192.168.1.255 > is a broadcast.
The 192.168.1.255 address is already the broadcast address as per my subnet mask, do I need a routing table entry even then? The situation is as follows:
my Linux servers address: 192.168.1.1 netmask: 255.255.255.0 broadcast: 102.168.1.255
Device is using address: 192.168.1.0 Device sends link broadcast to: 192.168.1.255
-- Jens-Uwe Mager <pgp-mailto:62CFDB25>
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