Thanks Lars - yes, I am not adamant about using twisted, although it seemed initially to be the best place to stary. I have also been looking at the pcapy module, which I think may do what I want, but also seems very low level.
On Wed, Mar 10, 2010 at 10:48 AM, Lars Ivar Igesund <lars...@gmail.com> wrote: > Hi Ben, > > my experience (not with Twisted, but with multicast), is that > multicast often fail to be properly routed (this may be a restriction > on OS, switch, etc). That you see the multicasts on using tshark is no > indication on the routing working properly, as it will catch all > information in promiscous mode, whether routed there or not. > > Two possible solutions (that may or may not be easy to in conjunction > with Twisted) are: > * Route the multicasts explicitly > * Make the listening socket bind explicitly to the network interface > where you expect/see the multicast. This is the solution I have used > myself, but may require using low level socket functionality. Binding > to localhost (all interfaces at once) or similar did not work for me. > > Best regards, > Lars Ivar > > On Wed, Mar 10, 2010 at 11:35 AM, Ben Barker <b...@bbarker.co.uk> wrote: >> Hello - I wonder if someone can help: >> >> We have some status info being sent by various machines using >> multicast addressed udp packets. I have been attempting to use twisted >> to write a python script that will passively monitor on the relevant >> port for any udp packets with the specified multicast address, which I >> can then parse the payloads of as required. >> >> I have been looking at the examples here: >> >> http://code.activestate.com/recipes/425975-simple-udp-multicast-client-server-using-twisted/ >> >> But I seem to have trouble getting them to receive anything at all. >> >> I have managed to use tshark to display the packets : >> >> tshark -i eth0 -x -l -f udp >> >> so I know the data is there (coming isn on address 224.0.0.4, port 901) >> >> Any suggestions? >> >> B >> >> _______________________________________________ >> Twisted-Python mailing list >> Twisted-Python@twistedmatrix.com >> http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python >> > > _______________________________________________ > Twisted-Python mailing list > Twisted-Python@twistedmatrix.com > http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python > _______________________________________________ Twisted-Python mailing list Twisted-Python@twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python
