DNS Resolver Speed Techniques
- by Rob Olmos
I recently received a reply to my concerns about some DNS servers being slower than others despite all servers being anycast:
In practice, most resolvers won't be
impacted by the slower paths to some
of the name servers in the set. Most
resolvers employ various techniques to
provide fast lookups, such as
preferring name servers that were
previously seen to be faster, sending
simultaneous queries to multiple name
servers, or pre-fetching queries
before the TTL has expired.
I was not aware that resolvers used these techniques and I was unsuccessful at searching for more info about this.
Are there any names for these techniques?
Which resolvers employ which of these techniques?
