Unless … are you writing a load balancer?
No, not quite. Good guess, but it’s almost the reverse.
The web applications I’m deploying are load balanced in several ways. One of those ways is to provide multiple A/AAAA records on DNS resolution, and the client resolver can decide on it’s own which IP address to hit. Typically each of those addresses are targeted at a load balancer, and behind the load balancer you have however many servers doing whatever.
On top of that DNS resolution is often geography sensitive so that requests can be “more local” – traffic is directed at local data centers.
Once in a rare while there is a network problem where one of the IP addresses published is not actually able to serve traffic for the published domain.
I’m writing software which attempts to detect this particular type of failure. It resolves a list of IP addresses from different geographically sourced IP addresses and targets each of those to ensure that they can all route traffic correctly. In order to do this I need to be able to target an SSL connection at each specific ip address and create an http request to the server as well.