Normally you point a domain name to an IP address(A record), but I want to do the opposite.
There's a firm that needs to call my API at www.example.com but the firm
says it can't call a domain name, they need a static IP.
I have an elastic IP that I can give them.
Now my question is, is it possible to point that IP to my domain name?
The reason I would like to do that is because my domain name has multiple A records(for DNS load balancing) and I wouldn't want to lose that.
So I would like(ideally) a situation where if you curl the IP address, it'll resolve to a domain name, then the domain name will resolve to the multiple A records and then get the API.
I'm on amazon infrastructure; ec2, route53 etc.
Yes, RDNS - reverse lookup. It is not really relevant though, because...
If they need a static IP, then they need a static IP. Likely their system is simlly programmed not to use any DNS lookup at all, and playing around with more unusual DNS setups is just not going to achieve anything besides wasting your time. For example. a RDNS entry would also not be evaluated by any NORMAL use of DNS (like a web browser), so while it technically answers your question with yes, practically it is not relevant.
No, that is not how the computer works. It will make a DNS lookup only if it does not get an IP address, excelt when asked to reverse resolve an IP address EXPLICITLY. CURL will never do that because it is not programmed like that.
Get a static IP address. A VM on Amazon with a VPN you log into from your office (which has the dynamic IP address) can achieve that.
No, this is not possible at all (to be clear: Not possible for your use case. See TomTom's answer where he talks about RDNS. This is not what you want).
Depending on the protocol, you could set up a load balancer on one static IP address and then forward the requests to multiple other servers.