DNS Nameserver updates affected by TTL? or is it just A records, MX etc

domain-name-systemttlwhois

The TTL has been set to 1H, so that IP changes for example.com can be made more quickly.

The registrar has been configured with ns1.example.com and ns2.example.com, verified using WHOIS lookup. ns1 and ns2 are based in Texas.

We're moving all of our stuff to New Jersey, because the new owner thinks it's a good idea.

So, we routed A records example.com, www.example.com, etc to New Jersey now, and that leaves ns1 and ns2 which are still based in Texas.

So, we set up new nameservers in New Jersey ns3.example.com, and ns4.example.com, and they are working well, but at this point the registrar/WHOIS is still set up to direct users to continue using ns1 and ns2.

I've been told that a 48-hour update is required for the WHOIS nameserver updates to take effect, so the logical course is to list the New Jersey DNS servers (ns3.example.com and ns4.example.com) on the WHOIS, then wait at least 48 hours before shutting down the Texas servers (ns1.example.com and ns2.example.com).

But, since the TTL is set to 1H, do I still need to wait 48 hours? Will public/recursive/ISP DNS servers cache the Registar/WHOIS nameserver list for longer than the TTL of the A records?

(I am not concerned about systems that ignore the TTL entirely, I'm only asking whether those that respect A record TTL will also use that same TTL for the Registar/WHOIS nameserver list)

Best Answer

You have to ask your registrar this question. Sometimes you can directly control your NS records and their TTLs, sometimes your registrar will have their own settings.

Related Solutions

DNS – How to Test Glue Record

Glue records only ever exist in the parent zone of a domain name.

Hence in the case of your example.org domain name, first find the .org name servers:

% dig +short org. NS
a0.org.afilias-nst.info.
a2.org.afilias-nst.info.
b0.org.afilias-nst.org.
b2.org.afilias-nst.org.
c0.org.afilias-nst.info.
d0.org.afilias-nst.org.

Then, for as many of these as you feel like testing, explicitly ask those name servers for the NS records for your domain:

% dig +norec @a0.org.afilias-nst.info. example.org. NS

You should get back the correct list of NS records in the "AUTHORITY SECTION". For any name servers that have correctly configured glue you should see those glue A (and/or AAAA) records appear in the "ADDITONAL SECTION".

DNS Migration – What DNS Settings to Use to Migrate Domain from One Server to Another

To keep things simple and do one thing at a time, you should not change your domain's NS records during this migration. If you want to migrate the web site and also migrate the authoritative DNS server, do it in 2 separate steps. To migrate the web site, change only the A and AAAA records.

A conventional "low value" TTL to set on the A and AAAA records is 300 (5 minutes).

If you can operate both servers at the same time for a short period, then you can do even better than a DNS-based migration. You can set the old server to proxy requests to the new server, so that clients which still contact the old server get their requests forwarded to the new server. This is easy to achieve with Apache with ProxyPass.

Later, if you want to move the DNS hosting, change the NS records and change the delegation in the parent zone (i.e. make the change at your domain's registrar). It is ideal if you can deploy the zone in the new servers ahead of time and leave both sets of nameservers serving the domain for a period of time.

EDIT: Details about ProxyPass

This Apache config snippet, placed in the <VirtualHost> section for your server, or directly in server config if there is no <VirtualHost>, will allow the old server to forward all requests to the new server:

<Location />
    ProxyPass http://www.example.org/
</Location>

You normally should have ProxyPassReverse with ProxyPass but in this case it can be omitted since it would have no effect because the old site and new site have identical ServerName.

You probably want to remove any other <Location>, Alias, RewriteRule, or other URL-mapping directives from the old server config at the same time to be certain that the proxy rule and only the proxy rule gets processed. (Keep a backup around, of course, in case you need to back out of your migration!)

Make sure the old server knows the correct new IP address for the web site's domain, otherwise it will proxy the request back to itself!

Best Answer

Related Solutions

DNS – How to Test Glue Record

DNS Migration – What DNS Settings to Use to Migrate Domain from One Server to Another

Related Topic