Reverse mapping allows users to send mail from your server and have the correct domain name appended to the outbound e-mail. This feature works almost exactly as the virtusertable, but in reverse. It is done with a “generics table” and requires the following lines be added to sendmail.mc: FEATURE(`genericstable', `dbm /etc/mail/genericstable')dnl GENERICS_DOMAIN_FILE(`/etc/mail/generics-domains')dnl In addition, you will need to create /etc/mail/genericstable, which is just like /etc/mail/virtusertable except that the columns need to be switched so that column one shows the local user name and column two shows the e-mail username and domain name you want that user’s outgoing mail to have. For example: tom email@example.com harry firstname.lastname@example.org tom2 email@example.com Restart Sendmail, and it should allow you to perform as a virtual mail host for multiple domains. You can usually restart Sendmail by passing it akill –1 [PID of Sendmail] or running /etc/init.d/sendmail restart.
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