Only in syslog-ng-1.9.9/src: .deps
diff -u syslog-ng-1.9.9.orig/src/gsockaddr.c syslog-ng-1.9.9/src/gsockaddr.c
--- syslog-ng-1.9.9.orig/src/gsockaddr.c	2006-02-11 18:37:02.000000000 +0000
+++ syslog-ng-1.9.9/src/gsockaddr.c	2006-03-28 11:41:14.058514000 +0100
@@ -91,6 +91,12 @@
         }
       rc = G_IO_STATUS_NORMAL;
     }
+
+  if (g_in_multicast(fd, addr))
+    {
+      return G_IO_STATUS_ERROR;
+    }
+  
   return rc;
 }
 
@@ -610,6 +616,41 @@
 
 #endif
 
+int
+g_in_multicast(int fd, GSockAddr *addr)
+{
+  struct ip_mreq mreq;
+#if ENABLED_IPV6
+  struct ipv6_mreq mreq6;
+#endif
+  
+  switch (addr->sa.sa_family)
+    {
+#if ENABLE_IPV6
+      case AF_INET6:
+	if (IN6_IS_ADDR_MULTICAST(&(((GSockAddrInet6 *) addr)->sin6.sin6_addr)))
+	  {
+            memcpy(&mreq6.ipv6mr_multiaddr, &((GSockAddrInet6 *) addr)->sin6->sin6_addr.s_addr), sizeof(struct in6_addr));
+            mreq6.ipv6mr_interface.s_addr=0;
+            if (setsockopt(fd, IPPROTO_IPV6, IPV6_ADD_MEMBERSHIP, &mreq6, sizeof(mreq6)) < 0)
+		return 1;
+	  }
+	break;
+#endif
+      case AF_INET:
+	if (IN_MULTICAST(ntohl(((GSockAddrInet *) addr)->sin.sin_addr.s_addr)))
+	  {
+            mreq.imr_multiaddr.s_addr=((GSockAddrInet *) addr)->sin.sin_addr.s_addr;
+            mreq.imr_interface.s_addr=INADDR_ANY;
+            if (setsockopt(fd, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreq, sizeof(mreq)) < 0)
+		return 1;
+	  }
+	break;
+    }
+  
+  return 0;
+}
+
 /* AF_UNIX socket address */
 
 /*+
diff -u syslog-ng-1.9.9.orig/src/gsockaddr.h syslog-ng-1.9.9/src/gsockaddr.h
--- syslog-ng-1.9.9.orig/src/gsockaddr.h	2006-02-11 18:36:32.000000000 +0000
+++ syslog-ng-1.9.9/src/gsockaddr.h	2006-03-28 11:34:32.508514000 +0100
@@ -73,6 +73,8 @@
 
 #endif
 
+int g_in_multicast(int fd, GSockAddr *addr);
+
 GSockAddr *g_sockaddr_unix_new(gchar *name);
 GSockAddr *g_sockaddr_unix_new2(struct sockaddr_un *s_un, int sunlen);
 
Only in syslog-ng-1.9.9/src: Makefile