I will deploy a web server, but I don't have much experience.
I would like to know what happens with mail that is send when the server is offline (restarting, maintenance, etc.).
When an internal user wants to send and receive mail, it's logic that he can't access the server. But when an external person uses his mail server to send a mail to my mail server, will the mail be resent on a later time?
The mail server will be a virtual machine, is this a good idea?