diff --git a/ipanat/src/ipa_nat_drvi.c b/ipanat/src/ipa_nat_drvi.c
index 8ba2bdb..cfda3e3 100644
--- a/ipanat/src/ipa_nat_drvi.c
+++ b/ipanat/src/ipa_nat_drvi.c
@@ -823,7 +823,7 @@
 																 prot, flags,
 																 fd, offset);
 #endif
-	if (NULL == ipv4_rules_addr) {
+	if (MAP_FAILED  == ipv4_rules_addr) {
 		perror("unable to mmap the memory\n");
 		return -EINVAL;
 	}