[zeromq-dev] RFC: zbeacon for dhcp-style discovery
arnaud at sphaero.org
Sat Nov 30 17:16:19 CET 2013
On 11/30/2013 03:49 PM, Michael Haberler wrote:
> I have a seemingly trivial problem where I currently have tunnel vision:
> if I send a directed UDP packet to the beacon socket, the s_beacon_recv () callback isnt called except if I force the destination address to broadcast (255.255.255.255; in which case tcpdump does display the packet)
> if I set the sender address to one of the interface addresses, the packet doesnt go out as per tcpdump and s_beacon_recv() isnt called
> I wonder if I stepped into some socket behavior which I overlooked? noecho is not the cause btw.
> - Michael
I just tried it with the python zbeacon and the only way I can send data
from socat to the socket is by specifying the broadcast option:
$ socat - UDP-DATAGRAM:255.255.255.255:5670,broadcast
works okay, I reveive an error in zbeacon because the filter doens't match.
$ socat - UDP-DATAGRAM:255.255.255.255:5670
2013/11/30 17:11:57 socat E sendto(3, 0x1ad99d0, 28, 0, AF=2
255.255.255.255:5670, 16): Permission denied
In netstat I see the socket only listening on the broadcast address:
udp 0 768 255.255.255.255:5670 0.0.0.0:*
I haven't read the docs but I guess this is normal socket behaviour?
i: freenode: sphaero_z25
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