Problem receiving UDP broadcast packets.

Chris Angelico rosuav at gmail.com
Wed Apr 20 03:24:35 CEST 2011


On Wed, Apr 20, 2011 at 11:15 AM, Grant Edwards <invalid at invalid.invalid> wrote:
>> Or can you simply use a stupid netmask like /1 that picks up all the
>> IP ranges? That way, the source-IP check wouldn't fail.
>
> That would require that the device somehow knows that it's not
> configured correctly and should change the netmask to /1.  The device
> doesn't have any way to know that, and it must respond to the
> discovery commands both before and after it's properly configured.

Was hoping that you could make such a change _only_ on the computer
that's receiving the data - that way it's only one change, the devices
don't need any tweaking. But if it can't be, it can't be.

> I've reread the protocol documentation and noticed that the device has
> to respond not only to broadcasts to 255.255.255.255 but also to
> subnet broadcasts send to subnets it's not on.  That pretty much
> clinches the requirement to use a raw socket. :/

Sounds to me like someone majorly abused IP to do weird things. Looks
like you're stuck doing the same weirdness, in whatever way you can
manage :| Sorry.

Chris Angelico



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