1

I have three domains from three different registrars (e.g. example.com, example.net, example.org). The DNS records for each domain is handled separately using the control panel of each registrar. I wish to centralize all zones to a single service by changing all Glue Records to point to a single DNS server say ns1.example.net.

The procedure i end up is:

  1. Create each zone on the new server.
  2. "Copy" all records (A, AAAA, MX e.t.c) from registrars to the equivalent zone.
  3. Change glue records on all domains to point to the new server ns1.example.net

However, I am troubled with the following:

  1. Any cached A-Record queries from clients or resolvers shouldn't be an issue since the records of my NS server will point to the same IPs just as the original records did. Is that correct?

  2. What about the NS record queries? Do clients or recursive DNS Servers cache NS record queries? If this is the case, then, there is a possibility as soon as I change the glue record, clients will try to query old DNS server (registrar`s).

Regarding No 2, the way I see it, if the registrar stops responding to DNS queries as soon as I delegate the zone to another server... then I am helpless. Do registrars foreseen such situations and keep serving queries, lets say for another 24 hours, from the time you change the glue records?

4
  • I hope you are planning to use some DNS hosting service and not building your own name server. There are too many pitfalls in building your own. – Tero Kilkanen May 24 '17 at 14:10
  • @TeroKilkanen Well, i do manage an NS server for my own personal domain which is something that i like, however, this case is different since we are talking about business production DNS records. I am also NOT thinking to add such an important service under my management, at least for now, hence i will use a third party. – giomanda May 27 '17 at 10:52
  • You are changing nameservers, not specifically glue records that have a specific meaning. Also to give you perspective, in one of my previous job at a registrar, when a client changed its nameservers from the registrar provided ones to its own set, we kept our servers configured for their zone for 7 days to make sure we still reply for queries (which made a very interesting/complicated SQL query to achieve that). Some registries contractually mandate registrars to do that, for example after a transfer. See .FR for an example. – Patrick Mevzek Feb 23 '18 at 6:51
  • 1
    Also more complicated setups are possible for a smooth transition but probably out of reach of the public due to the need of multiple actors cooperation. For example, the old set of nameservers could become slavves of the new ones for the concerned zone so that queries still arriving at the old nameservers would get answered exactly the same ways as if they arrived on the newer ones, including if you were starting to make changes in the zonefile. – Patrick Mevzek Feb 23 '18 at 6:52
2

1) Any cached A-Record queries from clients or resolvers shouldn't be an issue since the records of my NS server will point to the same IPs just as the original records did. Is that correct?

That is correct.

2)What about the NS record queries? Do clients or recursive DNS Servers cache ns record queries?If this is the case, then, there is a possibility as soon as I change the glue record, clients will try to query old dns server (registrar`s).

Regarding No 2, the way i see it, if the registrar stops responding to dns queries as soon as I delegate the zone to another server...then I am helpless. Do registrars foreseen such situations and keep serving queries, lets say for another 24 hours, from the time you change the glue records?

Yes, clients and servers cache NS RRs just like all other RRs.

You may be confusing registrars and DNS providers. For example, I use Dyn as my registrar and cloudflare as my DNS provider. If I were to change registrars the clouldflare DNS servers would still respond to queries for my domain until I deleted it from cloudflare's name servers.

If your registrar and DNS provider are the same you'll need to ask them. They could immediately reconfigure their name servers the moment you change the registrar away from them and servers / clients that have the NS RR cached will fail to resolve RRs in those domains.

That being said, that wouldn't be nice for a registrar/DNS provider to do that so they probably don't.

Aside: If you are going to be setting the NS records for domainA.net, domainB.net, domainC.net under mydomain.net (ns1.mydomain.net) you will no longer have glue records for those domains. You will for ns1.mydomain.net. What these means:

  1. These domains will require an additional DNS query since the NS RRs will not be in the additional info section which will cause a slight performance impact.
  2. You will be able to set the TTLs for the NS RRs for these domains. Typically glue NS RRs have 48 hour TTLs and you can't change that. E.g., dig ns cloudflare.net @192.5.6.30

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.