The virtual user table uses two configuration files.  The first, /etc/virtusertable, is a text file containing the alias definitions.  The second file,/etc/virtusertable.db, is generated by this procedure and is the actual alias database used by Sendmail.

1.Create or modify config file /etc/virtusertable

Each data line in the configuration file should be of the following format:

[username]@hostname forward
Where "[username]" represents an optional username portion of the original recipient address, "hostname" represents the host or domain name portion of the original recipient address, and "forward" represents the address to which the mail should be redirected.  If "[username]" is omitted, mail to any address within the given domain will be passed to the forwarding address.
For example, to forward mail addressed to "jqpublic@somewhere.com" to "joeuser@mydomain.net":
jqpublic@somewhere.com joeuser@mydomain.net

2.After creating or modifying /etc/virtusertable, you must execute the following command to make Sendmail aware of the new aliases:

makemap hash virtusertable.db < /etc/virtusertable