Sendmail feature wanted

[Paulo Henrique Baptista de Oliveira <baptista@linuxsolutions.com.br>]

      Hi All,
      I use Sendmail to send and recive mail through Internet but I want the 
following feature: when an e-mail comes to an unknow user, it will be delivery 
to a know user. 

      At Sendmail homepage, tells me to use a Virtual Domains and the command:
# makemap dbm /etc/mail/virtusertable > sourcefile
      to create the virtusertable.db. 
      But this command not works and give a error:
# makemap dbm /etc/mail/virtusertable > sourcefile
# makemap: Type dbm not supported in this version
      
      My version of sendmail is 8.9.3-23 from Debian Potato. 
      I try to use a BerkeleyDB3.1 but I dont understand how I can make a db
with this.
      If someone knows a way to do this work, I thanks so much.
      Regards,          Paulo Henrique