Hello, First of all I must let you know that I am new to Twisted. I need to implement a server discovery mechanism for my application. The way I chose to implement it is this: 1. The client, when started, sends a broadcast message requesting servers to make their presence known (UDP broadcast) 2. The server responds to this request using the same port on the sender's IP to reply (UDP normal message) 3. ... Now the problem I faced is that from the examples I found on the web (http://twisted.sourceforge.net/TwistedDocs-1.1.0/howto/udp.html), for multicast UDP messages, are done using listenUDP on both sides (server and client) and this approach is not good for me because I need a non-blocking communication mechanism on the client-side.