Windows – How to configure exim4 to orelay email from a specific IP

Your /etc/hosts file should have at least two records in it. The first record should be of the form:

<IP_ADDRESS> <HOST_FQDN> <HOSTNAME>

the second one should be of the form:

127.0.0.1 localhost

You also need to make sure that your /etc/hostname file contains the server's FQDN, and that running hostname -f returns your servers FQDN. If you make sure all of this is correct, and restart Exim, you should start seeing it HELO properly.

You could create /etc/exim4/conf.d/router/350_domain_redirect and use the following contents:

domain_fr_redirect:
   driver = redirect
   domains = domain.fr
   data = username@gmail.com

This will work, but is very specific to your problem. An improvement would be to look up the information from a file.

As for everything being in separate files, you can make the Debian exim4 packages use a single file by running:

# update-exim4.conf --keepcomments -o /etc/exim4/exim4.conf

If the exim4.conf file exists, then it will use that, otherwise, it will use the autogenerated file in /var/lib/exim4.