diff -Nur src/Ice/Network.cpp src/Ice/Network.cpp
--- src/Ice/Network.cpp	2006-06-29 00:52:03.000000000 +0200
+++ src/Ice/Network.cpp	2007-01-19 20:48:20.000000000 +0100
@@ -477,6 +477,21 @@
 	throw ex;
     }
 
+    if (IN_CLASSD(ntohl(addr.sin_addr.s_addr))) 
+    {
+	struct ip_mreq mr;
+ 
+	mr.imr_multiaddr = addr.sin_addr;
+	mr.imr_interface.s_addr = INADDR_ANY;
+	if (setsockopt(fd, IPPROTO_IP, IP_ADD_MEMBERSHIP, (char *)&mr, sizeof(mr)) == SOCKET_ERROR) 
+	{
+	    closeSocketNoThrow(fd);
+	    SocketException ex(__FILE__, __LINE__);
+	    ex.error = getSocketErrno();
+	    throw ex;
+	}
+    }
+
     socklen_t len = static_cast<socklen_t>(sizeof(addr));
 #ifdef NDEBUG
     getsockname(fd, reinterpret_cast<struct sockaddr*>(&addr), &len);