user@hostname or user@domainname

hi,
I'm using Postfix mail server (based on the howto guide by Falko). There's one thing i dont really understand:

with the virtual user, the email is in the format user@domain (e.g. [email protected])

with the system account email has format user@hostname (e.g. [email protected], or [email protected])

is this normal?

 

Of course you can make the system users have the user@domain format if you want, by adding the domain name to mydestinations.

 

thanks
should i remove the old mydestination values (which includes a fully qualified domain name)?

 

You don't need to remove the other mydestination values.

One thing you should note is that you cannot use domains in mydestination that you already use in the domains MySQL table.

 

what happens if i add a domain to both?

and,
if i reply to the email [email protected], the message should go the the virtual mailbox created based on the domain (/var/vmail/domain.com/user for example)

if i reply to the email [email protected], so where should it go to?