I have an Ubuntu 8.04 web server on which I had an exim4 installation. I had e-mail set up with a smarthost, but I changed it to local mail only using
dpkg-reconfigure exim4-config
The problem is now that e-mail is not delivered locally. No e-mail is delivered at all, actually.
Is there a way to completely reset the configuration of exim4, so that it works like in a new installation?
dpkg-reconfigure exim4-config again, and choose the correct options this time :-).
Exim4-config pops up with the dialog you get for dpkg-reconfigure when installed, so there's no real config that's 'like in a new installation'. Ever new installation is different.