For example, the following command delivers mail addressed to jd to johndoe@company.com:name: name1 [, name2, ...]
jd:johndoe@company.com
Note: Only the local part of an address can be aliased. For example, the following command is wrong and does not have the desired effect:
sendmail consults the alias database only after deciding that the message (as originally addressed) should be delivered locally, and after it has rewritten the address to contain only the local part.jd@big.university.edu:jd@company.com
An alias continuation line must start with a space or a tab. Blank lines and lines beginning with the number sign (#) are treated as comments.
If you are running NIS, sendmail can use the contents of the NIS alias database with the local aliases database by adding the following special alias to the /etc/aliases file:
+:+
This special alias tells sendmail to consult the NIS alias database if the alias cannot be found in the local alias database. When the same alias is specified in both the local and NIS aliases file, the local alias supersedes the NIS alias.