diff --git a/lib/prefix.c b/lib/prefix.c
index c692203..2afaa09 100644
--- a/lib/prefix.c
+++ b/lib/prefix.c
@@ -379,7 +379,7 @@
   if (pnt == NULL) 
     {
       ret = inet_pton (AF_INET6, str, &p->prefix);
-      if (ret != 1)
+      if (ret == 0)
 	return 0;
       p->prefixlen = IPV6_MAX_BITLEN;
     }
@@ -392,7 +392,7 @@
       *(cp + (pnt - str)) = '\0';
       ret = inet_pton (AF_INET6, cp, &p->prefix);
       free (cp);
-      if (ret != 1)
+      if (ret == 0)
 	return 0;
       plen = (u_char) atoi (++pnt);
       if (plen > 128)