DNS Path

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SKiTLz

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Aug 3, 2003
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Ok quick question. When you register a domain with a registra what role do they play in the resolve process?

You specify on their site the NameServers for your site. Is that just updating the entry in the root servers or in their own dns servers?

So does it go like this..

Request.... ISP DNS (not cached)..... lookup root server & finds nameserver..... nameserver directs to the right host...

or is it

request.... ISP DNS (not cached)..... lookup root servers * finds registras DNS server.... registra dns server returns domain nameserver... domain nameserver directs to the right host...

As you can tell Im a wee bit confused here..

Cheers
 
The registrar submits it to the backend registry system. Which in turn puts it into the Root DNS.
 
Originally posted by JTY
The registrar submits it to the backend registry system. Which in turn puts it into the Root DNS.
Click to expand...
ahh k. Thanks. What exaclty is the backend registry system?

This is why it takes a few days to propagate down the line?

In theory. My Registra goes out of business. The root server still has my domains nameservers so all would still work fine? Registras dont have to send regular updates or anything?
 
Each top-level domain is assigned to a managing body which maintains the records for domains within it. They are responsible for the registry backend for that top-level domain.
 
You register a domain. Generally when you register you set up a couple of nameservers to be authoritative for your domain. Those nameserver entries get placed in to the root DNS. Whoever runs those DNS machines is completely up to you and is generally independent of the registrar unless you want the registrar to do DNS for your domain for you.

Reverse lookups are different. The owner of the netblock that your machine has an IP in is always authoritative for the reverse lookups on that netblock. They can delegate those details to a different DNS server, but the owner of the netblock is always queried first.

Requests generally go from the requesting machine to the ISP's DNS server. If the ISP has a cached entry (IP) for the name you're trying to resolve that entry gets returned, no further requests are needed and that address is used for the machine. If there's no cached entry, the ISP DNS server makes a request to a higher-level DNS server, potentially all the way to the root DNS servers. The DNS servers point to the IP of the nameserver that's authoritative for the domain the name you're querying is on and your machine then queries that nameserver for the IP of the name you're trying to resolve.

To answer your question, if your registrar goes bust and you've got a domain registered with them, you'll be in good shape as long as the registrar isn't doing DNS for your domain. If your registrar is doing DNS for you, chances are good you'll have to move to a different DNS provider (or do it yourself, which isn't all that tough).

Note that if your registrar goes out of business you won't be able to update the nameserver or domain information that's in the top-level DNS servers simply cause individuals don't have authority to update the information for their domain without the aid of the registrar that is the listed registrar for that domain. If you've got control of your DNS servers and your entries are working, your registrar going under won't make things stop working but it could make updating nameserver information and the like later, as well as renewing your domain, problematic.

Responsible registrars should let those that register domains through them know that they are going away ahead of time and tell users who will be picking up domain administration for the old registrar.

Changes take a while to propagate because once the registrar updates the root DNS those changes must get spread around to the other root DNS servers. The root DNS servers don't constantly update each other; changes get passed along periodically. Once the change is visible on the other root DNS servers things should be resolvable from everywhere else as long as the lower-level DNS machines don't have an incorrect cached record for the name you're trying to resolve.

I've never had name updates take more than six or eight hours to propagate worldwide.
 
Awesome. Thanks fellas.

Explains everything pretty clearly for me. I have no problems understanding DNS on my side and worknig with DNS. Just never really knew how the backbone of it all works.

Cheers
 
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