undefined | Better HN

0 pointsasveikau6y ago0 comments

> no mainstream consumer OS runs a local recursive resolver

I think Windows might do something close. DNS client requests are cached on a per-machine basis through the DnsCache NT service. But I do not think getaddrinfo() and friends talk to that service via DNS, so strictly speaking it is not a recursive DNS server, though the resulting behavior is largely the same as if it were.

0 comments

akerl_6y ago

I think there’s a differentiation here between a local DNS cache (which does exist on some consumer operating systems) and a local recursive resolver.

The former lets the system reach out to an upstream resolver and caches the results. By contrast, a recursive resolver is responsible for starting at the root zone and recursing downward from there to resolve the requested domain (so when processing a query for “foo.example.org”, the recursive resolver queries “org”, then uses the NS records returned to query “org.example”, then uses the returned NS records to query “org.example.foo”)

asveikauOP6y ago

Yeah ok, that's a difference I hadn't thought of. In most local caching servers the next hop is going to be the ISP or similar, rather than going to the root.

j / k navigate · click thread line to collapse