VeriSign, Inc. VeriSign, Inc. This memo describes DNS iterative resolver behavior that results in a significant query volume sent to the root and top-level domain (TLD) name servers. We offer implementation advice to iterative resolver developers to alleviate these unnecessary queries. The recommendations made in this document are a direct byproduct of observation and analysis of abnormal query traffic patterns seen at two of the thirteen root name servers and all thirteen com/net TLD name servers. This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements.