Roundcube Default user for postfix

[pupilspace]

I have recently installed postfix and roundcube onto my server. I have gone through all the necessary processes to install roundcube. However i can't logon to roundcube as i don't know the default username and password.

Through the terminal on my Debian machine; i can login in and view my mail. For example:
mail -u demouser

Does anyone know the default username or password. Or how i can create a user with the password.

[alec]

There's no default user. You need to install IMAP server (e.g. dovecot) and create users there.