question about running email server with static IP

I am given a static IP by my ISP.

I dont want any domain name for now.

Say for example my static IP is 123.12.123.1234

I am going to run a email server ArgoSoft at home.

Can I just do say like - username@123.12.123.1234 ?

If I dont do domain name, then its all free, right?

I am so confused with MX Record.

Is there anything I can read up on? The manual is just not complete.

I am doing this to learn and put on my resume. Not much to do anything else with 340 kbsp upload.

Yes, you are right, if you use your static IP to receive mail, then it's all free (No need to pay for domain). I don't know if you have already configured the mail server. Most of mail server will accept mail to it's local IP by default. You have to just send mail to:

username@[123.12.123.1234]

Your are trying username@123.12.123.1234, that is wrong.
Remmember, everytime you want to send a mail to ip address of server use "[ ]" between your IP address...

Have Fun ~~~~

Don't forget to let me know it's working or not ....