[Twisted-Python] multicast multi-listen not working or just not working on OSX?

[jarrod roberson]

I am having a hard time getting multicast to work in Twisted. Code
snippets/examples I have found are either too old or just incorrect.

what is the correct way to write a protocol handler that will
multilisten on a multicast socket?

I am trying to add mDNS responder functionality to my application and
twisted complains that port 5353 is already in use. I know I can run
multiple copies of mDNSResponder from Apple, is this just a problem
with twisted on OSX or is it worse than that.

regardless is there a fix to get twisted to work, this application
will eventually be deployed in an linux or solaris environment so if
it is an OSX thing I can just find another box to test it on.