Sendmail has the virtusertable configuration file, that is built into the virtusertable.db file. The purpose of this file is to direct incoming email, for a particular domain, to a particular user. If you have multiple domains, you can separate the email login proceedures by specifying a different user name for each respective domain. Such a configuration would look like this:

@bgevolution.com bgevolution
@nodomain.com nodomain

In this type of configuration you would have a user “bgevolution” and a user “nodomain”, and you will be able to login to Dovecot separately for each one. Another configuration consolidates things a bit:

@bgevolution.com primaryuser
@nodomain.com primaryuser

In this configuration you will be able to login to Dovecot, as primaryuser, which will contain all mail sent to both bgevolution.com and nodomain.com. Also note that in these examples I have used no text prior to the “@” symbol. In this way your Sendmail will catch all incoming mail to either domain. If you want to restrict things a bit you can add your username; in this way only email, coming specifically to that user name, will be accepted.