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I have NameCheap DNS for my DNS hosting and a fully unmanaged VPS server that it points to for all my domains.

I'm going through and making sure everything is right and optimized, but my reverse DNS shows server.myhost.tld for some reason (I was using this subdomain before, but all memory of it should be deleted now) and a DNS scan reveals no PTR record exists (which is true). I have mailcow setup on this server, and it is fully deliverable both ways with my current DNS config, as is :80 & :443 to my webserver (all correctly addressed to domain.tld not server.domain.tld).

I have installed Bind, but I'm confused about how to proceed, can I setup a local zone for my PTR record, and not affect my hosted DNS - can a domain have multiple zones in this way? I have used local DNS, but for intranet purposes and not combined with hosted DNS also. How does this situation normally work?

MJHd
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PTR records are not set by your DNS provider, but by the owner of the IP addresses. You need to contact the IP address owner to find out how to set PTR records.

Michael Hampton
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  • Ok, and this is the answer I keep getting - so lets just say I went to ARIN, registered an address myself, and I intended to host at my house - then how would I do it? – MJHd Sep 16 '20 at 16:04
  • At your house? You wouldn't. Your ISP won't do that for you without a business class connection, and some not even with. But if you have a business class connection, they'll generally set PTR records for you. Not to mention you probably won't want to spend the thousands of dollars that IP address allocation would cost, nor the thousands more in hardware you'll need to actually use it. – Michael Hampton Sep 16 '20 at 16:06
  • Ok, I have IP transit to my house then - I'm looking for the technical answer here - SOMONE has this record physically stored somewhere, I'm trying to figure who, where, and how. – MJHd Sep 16 '20 at 16:07
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    The answer is still the same: Your ISP. – Michael Hampton Sep 16 '20 at 16:08
  • @MJHd The party that has the network that contains yours (could be ARIN in the extreme case in your example, otherwise the ISP that you deal with), would delegate the reverse zone for your network to the nameservers that you specify. – Håkan Lindqvist Sep 16 '20 at 16:10
  • Sorry for still being lost on this, but you're saying that A2hosting has an authoritative zone and record that lists my domain by name? Again, I don't understand because A2 doesn't know my domain name at all - Namecheap does. Does A2 have an SOA that is authoritative for me, and if so, how do they know my FQDN? Will they just use BIND or is PTR not part of standard DNS - this is more confusing than MX to me >D – MJHd Sep 16 '20 at 16:17
  • @MJHd Reverse DNS is not about who knows about your domain name, it's about who owns the IP network. The only connection to your domain name is in the data that you want to add there. – Håkan Lindqvist Sep 16 '20 at 16:25
  • Ok ok, I think I'm starting to get it, so my PTR will be under the NS's SOA, similar to how I can CNAME my domain to google.com if I feel like it - even if I don't have any awareness of what's going on with google.com? – MJHd Sep 16 '20 at 16:28
  • @MJHd I don't follow the "under the NS's SOA" bit, but I suppose there is some similarity in there being a reference between technically unrelated zones. – Håkan Lindqvist Sep 16 '20 at 16:36
  • Ok, I just mean that they will host it (once requested). Last question I promise. Will they use a standard DNS server just like if I had a local intra and was running a DNS server for my office, or is there some other technology at play? It just seems to work a little differently than other record types... – MJHd Sep 16 '20 at 16:48
  • @MJHd They could host the relevant `PTR` records or delegate the specific zone for your network (if applicable) to your specified nameservers by adding appropriate `NS` records. For the DNS side itself there is nothing special going on, they could run BIND or whatever. – Håkan Lindqvist Sep 16 '20 at 17:01
  • Got it - thanks so much for clearing that all up you guys. Really appreciate it – MJHd Sep 16 '20 at 17:03