RFC 2181:Clarifications to the DNS Specification
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... TTLs in sets of records with the same name, class, and type, ...


... TTLs for DNS records with the same label, class and type, and the issue of canonical names, what they are, how CNAME ...


... Each DNS Resource Record (RR) has a label, class, type, and data. It is meaningless for two records to ever have label, class, type and ...
... RR) has a label, class, type, and data. It is meaningless for two records to ever have label, class, type and data all equal - servers should suppress such duplicates if encountered. It is however possible for most record types to exist ...
... data all equal - servers should suppress such duplicates if encountered. It is however possible for most record types to exist with the same label, class and type, but with different data. Such a group of records is hereby defined to be a Resource Record ...
... A query for a specific (or non-specific) label, class, and type, will always return all records in the associated RRSet - whether that be ...



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