--- trickle-overload.c
+++ trickle-overload.c
@@ -302,7 +302,7 @@
 	    domain, type, protocol, sock);
 #endif /* DEBUG */
 
-	if (sock != -1 && domain == AF_INET && type == SOCK_STREAM) {
+	if (sock != -1 && (domain == AF_INET || domain == AF_INET6) && type == SOCK_STREAM) {
 		if ((sd = calloc(1, sizeof(*sd))) == NULL)
 			return (-1);
 		if ((sd->stat = bwstat_new()) == NULL) {