What is the best way to migrate DNS services to new IPs?
I have moved our hosting to a new address space. I must soon decomission the old DNS servers operating in the old address space. New DNS servers are already up and running. We host hundreds of domain names which now rely on the old DNS servers. To swap over, should I:
A.) Move the old DNS server names (ns1.mydomain.com, ns2.mydomain.com) to the new DNS servers and expect the registrars to figure out the change, or:
B.) Create new DNS server names (ns3.mydomain.com, ns4.mydomain.com) for the new DNS servers and ask everyone to manually update their domains at their registrars?
C.) Other options?
I don't know if option A is technically feasible. I suppose I would modify the A record for 'ns1.mydomain.com' on the old DNS servers to point to the new DNS server and expect this change to propogate to the root servers/registrars? Option B would certainly be a nuisance to our customers.
The only information that is changing is the ipaddresses of ns1.mydomain.com, ns2.mydomain.com?
Seems like as long as you reduce the TTL at least 24 hours before you do the switch of ns1.mydomain.com, ns2.mydomain.com to new ip addresses it should be seamless. Particularly since the old servers and the new servers will be reporting the same information.
Yeah, but its still a good idea to keep the old servers running (on the old ip's that is) for at least 3-4 days after you switch over, cause many isps cache the data for days, (ignoring, or multiplying the TTL).
Will all of the third-party registrars automatically update as well? I mean, there are LOTS of domains out there, registered through third-party registrars and nonetheless using our DNS servers. Will they automatically update to the new IPs? Or, will some still require manual updating of the IP addresses of the specified DNS servers?
Say, if your dns-servers are ns1.a.com and ns2.a.com, with their old ips glued at the registrar you registered a.com with.
Someone else, perhaps a reseller or something, has ns1.b.com and ns2.b.com, with the same ips as yours, basically making them look the same, but still "their own" so to say. I usually set this up for my resellers.
The reseller (or whatever) has the same ips glued with their registrar, so when you change yours at your registrar, they need to change theirs too, to point to the new ips. That is, if they point their domain, b.com, to ns1.b.com and ns2.b.com.
If you have a normal customer that simply points their domain at ns1.a.com and ns2.a.com, you dont have to do anything there. This also goes for resellers that point directly to ns1.a.com and ns2.a.com.
Now that didn't come out as simple as i wanted it to... but see if you can make sense of it
To my knowledge, none of our customers have done this. Yippee!!! [And even if one or two have done this, it's no big deal to work with them.]
So, I'm feelin' pretty good about this. To ask our customers to specify new name servers for hundreds of domains would've not only provoked a mutiny but would've taken months before we'd see 100% compliance, and then, probably only after cutting off the old DNS servers.
Yepp, then you should be able to pull it off without any trouble. Just do one thing at a time, and make sure you have a plan to begin with, like this:
1. Set up new nameservers, test with "dig", make sure they work
2. Change the glue ip adresses at your registrar
3. Wait at least 3-4 days, and expect most people to use the new nameserver within 24 hours
4. Kill the old nameservers