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Date: Mon, 30 Apr 2007 06:16:00 -0400
From: "David S. Madole" <david@madole.net>
To: "'Abraham K. Mathen'" <akmathen@hotmail.com>, 
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Subject: RE: Why can't I sendto() to 127.255.255.255
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> From: Abraham K. Mathen on Monday, April 30, 2007 5:54 AM
>
>   I wrote a short program (on FreeBSD 6.0), that attempts
> to call sendto() on a UDP socket, with 127.255.255.255 as
> the destination address. It failed - with errno 49 (EADDRNOTAVAIL).
> Setting SO_BROADCAST and IP_ONESBCAST did not help.

Perhaps because the matched route for that address points to lo0 on your sy=
stem and lo0 is not a broadcast-capable interface?

lo0: flags=3D8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 16384
        inet 127.0.0.1 netmask 0xff000000

Note that there is no "BROADCAST" flag. Just a guess.

David