dovecot mapping and postfix authentication

[madmare]

Hi,

Let's suppose i've a user called 'myuser' and a domain managed by my named called 'mydomain.com'

I want to map all mails that come to mymail@mydomain.com to the user myuser. how can i do that with dovecot

plus, how can i enable authentication under postfix. AKA that users need to log in in order to be able to send mails from my smtp server.

 

Thanks in advance,

Daniel