I am trying to configure Exim to send mails directly over LAN without DNS. I have added a new_router entry to the server with local interface x.x.x.x, however, when I try to send mail via Exim, it insists that I am trying to send the mail to myself. How can I fix this?
It appears that your Exim thinks x.x.x.x refers to your own machine. You more than likely have some configuration setting (local_interfaces, extra_local_interfaces or hosts_treat_as_local) that includes x.x.x.x. You need to review your settings and remove the entry.
By default, the manualroute router is intended to give you a remote host, but that can also be adjusted by adding self = send to your new_router configuration.