On 2020-11-05 17:53, Liam Farr wrote:
That would really depend on your ISP, for the likes of Spark/Voda/Vocus/2Degrees etc and their various sub brands I would say no it’s not, residential plans are low margin low-touch cookie cutter products.
Matching forward / reverse DNS is something that would creep into into their business product offering / scope, as it lets you could let self host services etc which I would consider a business feature.
!! There's a fair amount of difference in effort between putting a *couple* of *matching* entries, something like: $GENERATE A-B-C-D.ip.ISP.nz IN A A.B.C.D $GENERATE A.B.C.D IN PTR A-B-C-D.ip.ISP.nz. and providing *customised* reverse DNS (to a customer's matching forward DNS of their own domain). The $GENERATE wildcard pattern is something that takes a few minutes, once, and is then "low touch", and it's not that hard to make the entries *match*. I'd definitely agree that *customised* reverse DNS is a business feature, but it's still disappointing that many NZ ISPs either don't provide *any* reverse DNS at all for their residental customer IPs (ie, not even a pattern answer, just no answer), or if they do, don't/won't configure forward DNS (in their own domain!) to match those patterns. It's a pretty damming statement on the cooperation of the Internet if residental ISPs are *deliberately* not providing {any|matching} reverse DNS "so customers cannot run servers". Especially because ironically the lack of reverse DNS is most likely to affect *outgoing* *client* connections -- historically things like FTP servers, IRC servers, etc, were the ones checking the *client* had reverse DNS... there are very few protocols where the *client* check for the reverse DNS of the *server* :-) (But in practice, "has reverse DNS" has been a poor check for a decade, because so few networks are "well run" by 20+ year old standards of things like reverse DNS, or matching reverse/forward DNS.) Ewen