diff -Naur opendkim-2.7.1.orig/libopendkim/dkim-dns.c opendkim-2.7.1/libopendkim/dkim-dns.c
--- opendkim-2.7.1.orig/libopendkim/dkim-dns.c	2012-10-25 01:12:31.000000000 +0300
+++ opendkim-2.7.1/libopendkim/dkim-dns.c	2012-11-08 15:03:16.864335102 +0200
@@ -57,12 +57,14 @@
 dkim_res_init(void **srv)
 {
 #ifdef HAVE_RES_NINIT
-	struct state *res;
+	struct __res_state *res;
 
-	res = malloc(sizeof(struct state));
+	res = (struct __res_state *)malloc(sizeof(struct __res_state));
 	if (res == NULL)
 		return -1;
 
+	memset(res, 0, sizeof(struct __res_state));
+
 	if (res_ninit(res) != 0)
 	{
 		free(res);
@@ -99,13 +101,14 @@
 dkim_res_close(void *srv)
 {
 #ifdef HAVE_RES_NINIT
-	struct state *res;
+	struct __res_state *res;
 
 	res = srv;
 
-	res_nclose(res);
-
-	free(res);
+	if (res) {
+		res_nclose(res);
+		free(res);
+	}
 #endif /* HAVE_RES_NINIT */
 }