add alias/cname for www in aws route53 for IIS website

Question

I was using hosting with plesk panel until now, in plesk there would be a CNAME DNS record for the www record like this:

HOST             | Record Type | Value 
www.example.com. | CNAME       | example.com.

now in aws route 53, looking at docs and video tutorials I found 2 ways, one is to add 2 A records both pointing to the same IP of the webserver

and another way is to add 1 A record, and another A record as Alias for the first one

using both ways it will work depending on the hostname value in the IIS

so if the hostaname in IIS is set to www.example.com than only this url will work but the http://example.com won't work and if the hostname is example.com than the url with www won't work

my question is, what is the correct way to do this using route53

Answer 1

All of the options mentioned in the question will work.

What you did before will work on Route53:

example.com. A 192.0.2.1
www.example.com. CNAME example.com.

Or:

example.com. A 192.0.2.1
www.example.com. A 192.0.2.1

Or:

example.com. A 192.0.2.1
www.example.com. A <Route53 alias to example.com.>

On the IIS side, you'll need to add bindings for both example.com and www.example.com to the site. (It may be a good idea to set up an HTTP redirect from one of these to the other.)