[zeromq-dev] Multicast and wlan0

[Will Heger]

Some small progress maybe...

I ran tcpdump on my last configuration and no matter what I tried, for
the epgm stuff, nothing appeared on the wire.

So I installed the latest openpgm, upgraded to zmq 3.3-dev, and
re-installed pyzmq via pip.

Now when I run the epgm WITH and ONLY WITH the "eth0;" prefix
socket.connect('pgm://eth0;239.192.0.1:5000')

I get some noise (full output quoted at bottom):

17:16:13.849382 IP (tos 0x0, ttl 64, id 28125, offset 0, flags [DF],
proto UDP (17), length 54)
    192.168.2.101.58057 > 192.168.2.10.53: [udp sum ok] 57413+ A? eth0.rtr. (26)

And now my error reads:

  File "pro.py", line 6, in <module>
    socket.connect('pgm://eth0;239.192.0.1:5000')
  File "socket.pyx", line 493, in zmq.core.socket.Socket.connect
(zmq/core/socket.c:4960)
zmq.core.error.ZMQError: Invalid argument

Also interesting, my req/reply test  "eth0;" still doesn't work, but
my error looks the same:
Traceback (most recent call last):
  File "snd.py", line 5, in <module>
    socket.connect('tcp://eth0;192.168.2.100:5000')
  File "socket.pyx", line 493, in zmq.core.socket.Socket.connect
(zmq/core/socket.c:4960)
zmq.core.error.ZMQError: Invalid argument


But my noise looks like:

17:21:09.306180 IP (tos 0x0, ttl 64, id 36453, offset 0, flags [DF],
proto UDP (17), length 64)
    192.168.2.101.39415 > 192.168.2.10.53: [udp sum ok] 35562+ A?
eth0;192.168.2.100. (36)
17:21:09.322426 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto
UDP (17), length 139)
    192.168.2.10.53 > 192.168.2.101.39415: [udp sum ok] 35562 NXDomain
q: A? eth0;192.168.2.100. 0/1/0 ns: . SOA a.root-servers.net.
nstld.verisign-grs.com. 2012090701 1800 900 604800 86400 (111)
17:21:09.322634 IP (tos 0x0, ttl 64, id 36457, offset 0, flags [DF],
proto UDP (17), length 68)
    192.168.2.101.48578 > 192.168.2.10.53: [udp sum ok] 51453+ A?
eth0;192.168.2.100.rtr. (40)
17:21:09.349984 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto
UDP (17), length 143)
    192.168.2.10.53 > 192.168.2.101.48578: [udp sum ok] 51453 NXDomain
q: A? eth0;192.168.2.100.rtr. 0/1/0 ns: . SOA a.root-servers.net.
nstld.verisign-grs.com. 2012090701 1800 900 604800 86400 (115)


I can't really afford to spend any more time on the pgm approach.  I'm
going to concentrate on UDP broadcast and scanning now for my network
discovery strategy and hope that's more fruitful.  It's probably safer
and simpler considering I can write-off the pgm dependency even if
it's less elegant.

Thank you for everyone's assistance,
-Will



> 17:16:13.849382 IP (tos 0x0, ttl 64, id 28125, offset 0, flags [DF], proto UDP (17), length 54)
>     192.168.2.101.58057 > 192.168.2.10.53: [udp sum ok] 57413+ A? eth0.rtr. (26)
> 17:16:13.849517 IP (tos 0x0, ttl 64, id 28126, offset 0, flags [DF], proto UDP (17), length 54)
>     192.168.2.101.58057 > 192.168.2.10.53: [udp sum ok] 23207+ AAAA? eth0.rtr. (26)
> 17:16:13.850153 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto UDP (17), length 54)
>     192.168.2.10.53 > 192.168.2.101.58057: [udp sum ok] 57413 NXDomain q: A? eth0.rtr. 0/0/0 (26)
> 17:16:13.850555 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto UDP (17), length 54)
>     192.168.2.10.53 > 192.168.2.101.58057: [udp sum ok] 23207 NXDomain q: AAAA? eth0.rtr. 0/0/0 (26)
> 17:16:13.850636 IP (tos 0x0, ttl 64, id 28125, offset 0, flags [DF], proto UDP (17), length 50)
>     192.168.2.101.48581 > 192.168.2.10.53: [udp sum ok] 15088+ A? eth0. (22)
> 17:16:13.850692 IP (tos 0x0, ttl 64, id 28126, offset 0, flags [DF], proto UDP (17), length 50)
>     192.168.2.101.48581 > 192.168.2.10.53: [udp sum ok] 4674+ AAAA? eth0. (22)
> 17:16:13.862961 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto UDP (17), length 66)
>     192.168.2.10.53 > 192.168.2.101.48581: [udp sum ok] 15088 q: A? eth0. 1/0/0 eth0. A 67.63.55.3 (38)
> 17:16:13.867917 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto UDP (17), length 50)
>     192.168.2.10.53 > 192.168.2.101.48581: [udp sum ok] 4674 q: AAAA? eth0. 0/0/0 (22)