On a Debian Lenny server 'example.net', we have some cron jobs that need to send mail to 'firstname.lastname@example.org'. The MX for the domain is an offsite dedicated SMTP server. Exim is using the system-aliases router to find the local user, and not finding him:
$ exim -bt email@example.com R: system_aliases for firstname.lastname@example.org email@example.com is undeliverable: Unrouteable address
/etc/aliases we have the normal redirect for system users to root, which I'd like to keep.
What is the best way to have exim send mail for users that aren't found locally to the SMTP host specified through dnslookup?