.forward Files

Users can create a .forward file in their home directories that sendmail uses to temporarily redirect mail or send mail to a custom set of programs without consulting a system administrator. When troubleshooting mail problems, particularly problems with mail not being delivered to the expected address, always check the user's home directory for a .forward file.

A common mistake users make is to put a .forward file in the home directory of host1 that forwards mail to user@host2. When the mail gets to host2, sendmail looks up user in the NIS or NIS+ aliases and sends the message back to user@host1, resulting in a loop, and more bounced mail.