Send the ZreMsg to the socket. Warning re WHISPER and SHOUT: The 0MQ spec http://rfc.zeromq.org/spec:36 says "message content defined as one 0MQ frame. ZRE does not support multi-frame message contents." ...on the other hand, it appears that zeromq/zyre also supports multi-frame contents, as per the top of zyre.c This C# implementation allows multi-frame contents.