[hvindin]

This.

I'm kind of suprised that I can't see any other comments talking about GTM's (I assume you mean F5 Global Traffic Managers)

Where I am at the moment GTM's are used everywhere, and everywhere the TTL is set to 30s.

The only part of this that really annoys me is that the global default configuration, rather than serving up a subset of the list of IP addresses, only a single IP address is returned when you resolve down to the A record.

When I've pressed the issue that _at least_ on our internal GTM's we should just return a bunch of IP addresses every time someone resolves the address, I've been told that it would break load balancing... which blows my mind because who on earth is relying on DNS to load balance traffic with a 30s TTL, I would have thought that the normal thing to do, if you actually wanted load to balance, would be to result a subset of IP addresses in a different order and with a different subset each time. That way other DNS servers which resolvers that will cache that record can at least be returning multiple addresses to all the clients it serves, as opposed to everyone using that resolver getting stuck to a single address for 30 seconds...

But all of that being said, it would make perfect sense to me to just return like 4 IP addresses publicly for every resolution and rotating setting the TTL to like 30s so that clients could spend 30s iterating through the A Records they have cached, then hit your resolver up again and get a different sites addresses back if your site had gone down...