You're right. I did some experiments too after your first reply. It's definitely inconsistent depending on what software you are using (as some software now byp

You're right. I did some experiments too after your first reply. It's definitely inconsistent depending on what software you are using (as some software now bypasses your system resolver and uses HTTP DNS etc). I've known people who had email addresses on TLDs and they never had any problem receiving email (without using a final dot), so I'm not sure how the MX record is being resolved or how the SMTP connection is being made. It's very possible that the mail daemon is automatically adding a dot to the end of every hostname.