Aliases that are listed in a .mailrc file are accessible only by the user who owns the file. This restriction enables users to establish an alias file that they control and that is usable only by its owner. Aliases in a .mailrc file adhere to the following format.
alias aliasname value value value ...
aliasname is the name that the user uses when sending mail, and value is a valid email address.
If a user establishes a personal alias for scott that does not match the email address for scott in the name service, an error occurs. Mail is routed to the wrong person when people try to reply to mail that is generated by this user. The only workaround is to use any of the other aliasing mechanisms.