Robust Domain Name Resolution

摘要

A recursive DNS nameserver system and related domain name resolution techniques are disclosed. The DNS nameservers utilize a local cache having previously retrieved domain name resolution to avoid recursive resolution processes and the attendant DNS requests. If a matching record is found with a valid (not expired) TTL field, the nameserver returns the cached domain name information to the client. If the TTL for the record in the cache has expired and the nameserver is unable to resolve the domain name information using DNS requests to authoritative servers, the recursive DNS nameserver returns to the cache and accesses the resource record having an expired TTL. The nameserver generates a DNS response to the client device that includes the domain name information from the cached resource record. In various embodiments, subscriber information is utilized to resolve the requested domain name information in accordance with user-defined preferences.

主权项

1. A computer-implemented method of processing domain name system requests, comprising:
storing at a recursive nameserver domain name records for a plurality of domain names including a first domain name; issuing a domain name system (DNS) request for the first domain name to one or more authoritative nameservers associated with the first domain name after said storing; in response to a failure associated with the DNS request for the first domain name, identifying a subset of the plurality of domain names that are associated with the one or more authoritative nameservers, the subset including the first domain name and at least one additional domain name of the plurality of domain names; and modifying the domain name records at the recursive nameserver for the subset of domain names in response to the failure associated with the DNS request for the first domain name.