The would lead the host to believe that the domain did not exist, when in fact there was a perfectly valid IPv4 A record that, if returned, would have resulted in the host at least making a connection over IPv4.īecause these older DNS resolvers could not handle a AAAA query or response correctly, the IETF issued RFC 4074 “ Common Misbehavior Against DNS Queries for IPv6 Addresses”. If a host sent an ANY query or an IPv6 AAAA DNS query to a resolver which was not IPv6-literate, the resolver would return an erroneous response code ( RCODE) such as NXDOMAIN. The reason that there are separate IPv4 A record and IPv6 AAAA record DNS queries is that early IPv6 deployments occasionally encountered problems with older IPv4-only resolvers. And today, frankly, all hosts are dual-protocol bilingual and can use either IP version (4 or 6) for their DNS traffic or for the DNS queries and responses contained within.
One aspect of dual-protocol behavior that often surprises peoples is that hosts send two separate DNS queries to their resolver. The method that networked devices use to find their way around the digital ocean is the Domain Name System (DNS), which translates human-readable host and domain names into numerical IP addresses (and vice versa). Thankfully, navigating the Internet is not as daunting. Imagine what it was like to be an ancient mariner navigating the ocean blue at night using nothing more than stars, a sextant and a marine chronometer.
0 kommentar(er)
