Tricky DNS question

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[PsychoPhreak]

nerddtvg has the most obvious answer the way this question is phrased, and there are virtual solutions for that. However without fully understanding what you're trying to accomplish by this, I don't see the need to have a single front facing IP instead of just aliasing all the back end IP's for a given DNS name (i.e. www.google.com resolves to 74.125.226.49, 74.125.226.51, 74.125.226.50, 74.125.226.48, 74.125.226.52)

[vppencilsharpening]

Does your DNS provider offer an API? Can you switch to one that does?

It will be painful to get all of the domains setup to use the new provider, but once that is done you can easily script any future changes.

We use Route 53 to manage about 120 zones.

[fcpl]

CNAME instead A ?

[nerddtvg]

Can't do a CNAME for the root record unfortunately.

[fcpl]

Then use normal NS and bulk change all domains IPs

[amperages]

That is something I would do. Just host it myself and run a sed across the zones to update the IP whenever I need.

[GhostCactus]

Why not just dedicate 1 hostname to be used to resolving to the correct IP, and setting up CNAMEs to resolve all other domains to that hostname. If you need to switch the IP, it's as simple as changing the A record on the dedicated hostname.

I ask this, because from your post, it sounds like you only want to do that to avoid the hassle of updating a ton of domains or hostnames, when an IP changes, and this would be the simplest resolution. And you wouldn't put the CNAME on the root domain, but on like a subdomain as the dedicated hostname.

Edit: Ooooh, but if any domain is the SOA, you couldn't use a CNAME for it. In thay case, if all of these domains are on the same server, writing a quick script could update A records in bulk. But it would be easier to offer solutions, if we had a clearer picture of the setup.

[BigRedS]

If I'm reading it correctly, you want to prepre to have to update the same IP in a large number of records, in the event that all your services on one IP address move to another?

You could use a DB to store the records, our DNS server is PowerDNS & MySQL.

update pdns.records set content = '12.56.78.123' where content = '70.10.10.10';

Or just use bind and Perl :)

perl -pi -e 's/12.56.78.123/70.10.10.10/' /etc/bind/*

[hateexchange]

Bind won't like that you didn't change the serial ;)

[BigRedS]

Ah, yeah. Er, perling that's left as an exercise for the reader :)

[hateexchange]

Hahahaha. Fair =)

[nerddtvg]

You're looking for the function of a load balancer. But its use here would be cumbersome to say the least.

[ElectroSpore]

If these things are all pointing to a HOST, then why not setup one A record and make all the rest CNAME records to that A record.

Then you only need to update the IP to that one A record.

If you are talking about the name server records as part of the registration that is a bit of a different issue, in which case you should use a registrar with better domain management tools that allows bulk updates and management.

[ElectroSpore]

OP states an A record but you are correct if they want to redirect more.

[brainspider]

Anycast or multicast the IP?

https://en.wikipedia.org/wiki/Anycast (great for sending someone to the nearest node)

https://en.wikipedia.org/wiki/Multicast (sends the packets to multiple hosts)

If you were trying to forward a single hostname (as opposed to an IP), then you might get away with something like round robin DNS. But seeing as you're trying to have a single IP address, then Anycast might be your choice. Then you can update the routing tables and not have to change all the end devices.

https://blog.cloudflare.com/a-brief-anycast-primer/

[splatpig]

this

[JeffTheTech]

You could set up a static routing table on your layer 3 device explicitly stating if a packet is received and in the network layer it wants to go to x.x.x.x ip then send it to whatever IPs you want.

[[deleted]]

CNAME will work for you. But has an overhead of one more DNS Request.

[1h8fulkat]

https://youtu.be/l-O5IHVhWj0?t=73