If you must have a default mail drop for your virtual hosts, they must be listed at the lowest portion of the /etc/mail/virtusertable file so all other aliases for the domain may work as the Server reads this file in order. This will not allow you to have any POP accounts as they will be forwarded to the default mail drop however, you may work around this by setting an alias that will send the message to the “user@virtualdomain.com” which will then drop the message to the POP account “user” and your virtual domain may POP for the messages as long as they have the proper credentials. Keep in mind that the server only looks for the “usernames” when receiving messages which allows this method to work unless an alias is involved which will then forward the message to the appropriate location.
Example Virtusertable:
aittest@virtualdomain.com aittest@topleveldomain.com
@virtualdomain user@anydomain.com
The above will drop any e-mail coming into the server for “aittest@virtualdomain.com” to the mailbox “aittest”. If any e-mail is sent to an unspecified user “@virtualdomain.com” the message will be forwarded to “user@anydomain.com”.