sendmail - sending/receiving external email without a domain name? -

I want to set up a mail server to send emails and receive external emails (from another server to Internet) either Postfix in sendmail or unix or hMailserver on windows. Because it is easy to set up a web server, because people can access the Internet without the need of a domain name, and works like any other web server using the domain name. I was wondering if it is possible to set up the mail server, which can work with the IP, just like any mail server at the work of the internet

The email addresses will be as follows:

example@my.ip.is.here

If this is not possible then Would it be possible that the domain name type A (my IP is linked in a way, the domain name)?

Thank you.

Unfortunately, you can not send mail from your IP address: D hook you can also make free servers Or, like you put your domain in the mailsaver.