Understanding /etc/aliases

Question

I know that /etc/aliases is used to provide mail alias for system users (for either Sendmail or Postfix), for example, the listing like those in Understanding /etc/aliases and what it does.

However, can I use names beside system users? I.e., if I want to use an alias softball, do I need to create that softball user account first?

I've gone through the following docs, but still am not sure about it.

• https://unix.stackexchange.com/questions/65013/understanding-etc-aliases-and-what-it-does
• http://docs.oracle.com/cd/E19683-01/806-7612/mail-45/index.html
• http://docs.oracle.com/cd/E19253-01/816-4555/mailrefer-35/index.html
• https://docs.oracle.com/cd/E36784_01/html/E36828/mailadmin-106.html
• http://bsdwiki.reedmedia.net/wiki/Create_or_modify_email_aliases_for_Sendmail_or_Postfix.html
• https://www-01.ibm.com/support/knowledgecenter/ssw_aix_53/com.ibm.aix.files/doc/aixfiles/aliases.htm
• https://www.freebsd.org/doc/handbook/sendmail.html

Thanks

Answer 1

The alias source can be anything. That's pretty much the point of aliases – many systems will have entries like postmaster: root without a matching OS account.