diff --git a/libraries/libldap/url.c b/libraries/libldap/url.c
index e5909bac41..00413dc088 100644
--- a/libraries/libldap/url.c
+++ b/libraries/libldap/url.c
@@ -355,7 +355,7 @@ char * ldap_url_desc2str( LDAPURLDesc *u )
 	};
 
 	if( u->lud_port ) {
-		len+=6;
+		len += sizeof(":65535") - 1;
 	}
 
 	if( u->lud_host ) {