2. Introduction

Several problem areas in the Domain Name System specification [RFC1034, RFC1035] have been noted through the years [RFC1123]. This document addresses several additional problem areas. The issues here are independent. Those issues are the question of which source address a multi-homed DNS server should use when replying to a query, the issue of differing TTLs for DNS records with the same label, class and type, and the issue of canonical names, what they are, how CNAME records relate, what names are legal in what parts of the DNS, and what is the valid syntax of a DNS name.

Clarifications to the DNS specification to avoid these problems are made in this memo. A minor ambiguity in RFC1034 concerned with SOA records is also corrected, as is one in the definition of the TTL (Time To Live) and some possible confusion in use of the TC bit.