ISPs (at least in the US) have a slippery slope when "altering" DNS queries. There's an implied transparency there which, while I can't speak for all, at least some try to maintain.
What IS pretty easy, and not outside the realm of possibility, is putting a CDN-style request router in as and NS for the domain and that request router can return the ISP's own (or closer) hosts based on the DNS-referer payload. Alternately, the request router can attempt to lookup the source ISP of the caching resolver based on public tools and ISP identifiers and/or whois. That kind of thing is available today, just not typically employed for traffic steering outside a content delivery network. Check out the open-source CDN work released by Comcast (and contributed and enhanced by others) which is based on Apache Traffic Service. Dan ----- Original Message ----- > From: "Daniel Frank" <[email protected]> > To: "pool" <[email protected]> > Sent: Sunday, February 19, 2017 3:51:40 PM > Subject: Re: [Pool] Configurable reply for *.pool.ntp.org ? > On Sun, Feb 19, 2017 at 06:49:38PM +0100, Rob Janssen wrote: >> How about providing a feature in the pool DNS to configure a preferred set of >> servers for >> requests that were made from some specified resolver? >> >> That way the customers of some ISP could be directed to the timeservers >> provided >> by that ISP, >> and similar for other networks that have good timeservers and a DNS resolver. >> It would relieve > > The idea is somewhat interesting, as it probably would take load off some ntp > servers. But instead places a notable higher load on the pool dns servers, as > they now have to query an additional database to check for any special rules > and probably the vast majority of these queries will return "nothing special, > continue with normal procedures". > > Just a thought: ISP Networks usually have their own DNS resolvers, and could > manipulate the pool responses to point to their own servers, unless they are > signed. So no additional load on the pool DNS servers, and reduced load on ntp > servers. Though that's probably far outside of the best practices in the DNS > world. > > Regards, > Daniel > > _______________________________________________ > pool mailing list > [email protected] > http://lists.ntp.org/listinfo/pool -- Dan Geist dan(@)polter.net _______________________________________________ pool mailing list [email protected] http://lists.ntp.org/listinfo/pool
