--- crypto/heimdal/lib/krb5/addr_families.c
+++ crypto/heimdal/lib/krb5/addr_families.c
@@ -142,7 +142,7 @@
 {
     const struct sockaddr_in *sin4 = (const struct sockaddr_in *)sa;
 
-    if ((ntohl(sin4->sin_addr.s_addr) >> 24) == IN_LOOPBACKNET)
+    if (IN_LOOPBACK(ntohl(sin4->sin_addr.s_addr)))
 	return TRUE;
 
     return FALSE;