The rumor I heard was that if you operate a small email service and need to get Google to recognise your server and accept inbound email for gmail recipients, admins of those services must do a dance and go through various hoops like solving a CAPTCHA before their server’s IP address is whitelisted. (Is that true? I have never tried.)

Question 1:
Does Microsoft do the same thing as Google? Are there any hoops or obsticles to getting MS’s mail server to accept mail from a new mail server?

Question 2:
If an admin of a small service decides to do the same, and force sending servers to solve a CAPTCHA to get whitelisted, what does Microsoft do when their server encounters that barrier? Is there reciprocity, or does MS just do the bullying that it does and simply let outbound MS email get blocked at the destination?