All of it is done on the SMTP server itself.
Basically you created the from address for the device on a mail server somewhere.
That from address (lets call it Xerox@company.com) needs to be set to relay (Forward) emails to the outside world (Outside of company.com's domain)
For each type of server there are slight variences, but typically it is that you associate the from address to an IP address (Printers) and allow it to relay.
Typically this happens when the device is set to a server that does not support sending outside of the domain (one listed above for example with Gmail) or when there was an issue with authentication, so email was setup via port 25.