richard lucassen <mailinglists@???> wrote:

>> And what I was saying is: You should run one on modern networked *ix
>> machine generally. Because it's 2016.
>
> I do not agree.

+1

> If the local machine generates quite a bunch of queries
> than you're right. So, if you have (in 2016) let's say forty servers
> running in a network, they are all going to query the root servers? I
> think it's better to have one resolver that does the job for such a
> network. But you're right to install a caching DNS on a server that
> makes a lot of queries. I'd use that caching DNS as a forwarder to the
> central DNS and not one that is going to bother the root-servers.

Unless you have just one device on your network, then you should not be running a recursive resolver on each of them - that's just being antisocial to the internet.

And the reason ISPs run recursive resolvers for their customers ? That's easy to answer. 99.99something percent of those customers are (in general) not technical people. So if the ISP supplies a pre-configured (or auto provisioning) router, which automatically uses the ISPs DNS resolvers (typically in the UK, supplied via the PPP sign-in process) - then they can be reasonably certain that their customers can "open box, plug in router, get on internet" **without** tying up expensive helpdesk man hours.

Tech savvy customers like us can ignore those resolver and do our own thing - I too have split horizon DNS.