Not sure how to ask this question.
I set up a SMF forum recently with fantastico. It seems to be working fine.

When I tested a new forum user it sent a welcome email from an address I didn't know I had.
It came from "username@mydomain". Username being my cpanel login name. I tried to reply to that address and got a undeliverable message (no such address). I changed SMF to use a valid email and a subsequent test worked OK. So that's fine.

In cpanel I clicked on the webmail icon and found several messages from "username@localhost" (again username being my cpanel login name).

I guess my question is "what is this email account that gets messages from the server but is not accessible from outside of cpanel?"

I hope that makes more sense to you guys than it does to me.

Thanks. Ken.

Thanks for the info Mitch FTW.

I also figured out I need to check that mail box periodically. It told me I needed to update SMF, Which I did and it worked fine.
 
Thanks. Ken.