Force exim to send email from a particular IP

If you need to change the IP that is used to send email out of your systme, you can do so by editing your /etc/exim.conf.
Change:

remote_smtp:
driver = smtp
to:

remote_smtp:
driver = smtp
interface = 1.2.3.4
Where 1.2.3.4 is the IP you want exim to use.