cyrus-imapd virtual domains

[Jesus Ruiz]

Hello, i'm trying to configure a cyrus-imapd server to server virtual
domains. I have several mail customers with their own domain. I wonder
if there is a way to make cyrus authenticate all the users from any
domain only with their username not using username at domain.

I have read that cyrus have a default domain, and the users from this
domain don't need to log using username at domain.

If there is  way to do this, can someone please send me suggested
readings to make this work with sendmail.

Thank you very much