--- gated-3-5-10/src/task.c~	Sun Jul 12 12:46:02 1998
+++ gated-3-5-10/src/task.c	Thu Oct 29 13:19:41 1998
@@ -4812,7 +4812,26 @@
 
     setsocketopt:
 	if (!BIT_TEST(task_state, TASKS_TEST)) {
-	    rc = setsockopt(tp->task_socket, level, opt, ptr, len);
+
+#ifdef IP_MULTICAST 
+#ifdef linux
+#if LINUX_VERSION_CODE < 0x020100
+	  /* Linux 2.0.x multicast address hack to fix interface ifconfig
+	   * down then ifconfig up problem
+	   * This problem has something to do with kernel internals and the 
+	   * multicast address list on an interface getting cleared when
+	   * it physically goes down...
+           */
+	  if(option == TASKOPTION_GROUP_ADD) {
+	    /* CLEAR the kernel multicast address so that we can reinitialise
+	     * the kernel's multicast address list on the multicast interface
+	     */
+	    setsockopt(tp->task_socket, level, IP_DROP_MEMBERSHIP, ptr, len);
+	  }
+#endif
+#endif
+#endif /* IP_MULTICAST && Linux */
+	  rc = setsockopt(tp->task_socket, level, opt, ptr, len);
 	}
 	break;