FAQ / Routing for local delivery / Q0411
Q0411
Question
Why will Exim deliver a message locally to any username that is longer than 8 characters as long as the first 8 characters match one of the local usernames?
Answer
The problem is in your operating system. Exim just calls the getpwnam() function to test a local part for being a local login name. It does not presume to guess the maximum length of user name for the underlying operating system. Many operating systems correctly reject names that are longer than the maximum length; yours is apparently deficient in this regard. To cope with such systems, Exim has an option called max_user_name_length which you can set to the maximum allowed length.
FAQ / Routing for local delivery / Q0411