Howto: redirect a copy of your emails to another server while saving it locally

[consultorpc]

Hello,

We are posting this here in case it helps someone. With a few config changes on exim you can redirect your messages to an external server while keeping a copy locally.

First thing is to add a route for it.

Go to WHM -> Exim Configuration Editor -> Advanced Editor. Search for "ROUTERS CONFIGURATION" and add the following text on the textarea below it:

smarthost:
	driver = manualroute
	domains = yourdomain.com
	unseen
	transport = remote_smtp
	headers_add = X-Custom-Forwarded: true
        condition = ${if match {$h_X-Custom-Forwarded:}{true}{false}{true}}
	route_data = "aspmx.l.google.com"

In this case, we are redirecting all message sent to yourdomain.com to google's server. Change it according to your needs.

After that, you have to create a system filter. Create file /etc/custom_cpanel_exim_system_filter ( by default Cpanel use /etc/cpanel_exim_system_filter but upcp usually overwrites it when a new version is out ) and add this:

if first_delivery
	and $h_X-Custom-Forwarded contains "true" 
then
   seen
   finish
endif

This filter is necessary to avoid infinite loops in case the other email server is also redirecting back to you.

Now, go to WHM -> Exim Configuration Editor -> search for filter add edit System Filter File to point to /etc/custom_cpanel_exim_system_filter.

Save the new configuration and you are done.

Note: watch exim log to make sure everything is working fine.

In case something went wrong, you can always revert things by removing the changes on /etc/exim.conf.local and running /scripts/buildeximconf to build a new configuration. Don't forget to restart exim.

Hope it helps someone.

[cPanelTristan]

Is there a reason that the advice is being provided to manually edit /etc/exim.conf.local rather than putting this into WHM > Exim Configuration > Advanced Editor section?

[consultorpc]

No, just thought it was easier to explain this way rather than saying to edit 5th box on advanced editor, which could make someone insert it at the wrong place.

After all the result is the same, no?

[cPanelTristan]

The file /etc/exim.conf.local doesn't exist on my newly formatted machine. It only exists if you've made changes in WHM > Exim Configuration Editor > Advanced Editor in the past, so it isn't the same result for many people as that file will not exist.

To show the results, here is my machine before I made changes in Advanced Editor:

root@host [/etc]# ls -lah /etc/exim.conf*     
-rw-r--r-- 1 root root 47K Aug  8 17:10 /etc/exim.conf
-rw-r--r-- 1 root root 26K Feb 18 09:11 /etc/exim.conf.dist
-rw-r--r-- 1 root root  95 Aug  3 17:03 /etc/exim.conf.localopts
-rw-r--r-- 1 root root 30K Feb 18 09:11 /etc/exim.conf.mailman2.dist
-rw-r--r-- 1 root root 30K Feb 18 09:11 /etc/exim.conf.mailman2.exiscan.dist

Here is my machine after I added something in Advanced Editor:

root@host [/etc]# ls -lah /etc/exim.conf*
-rw-r--r-- 1 root root 47K Aug 10 11:22 /etc/exim.conf
-rw-r--r-- 1 root root 26K Feb 18 09:11 /etc/exim.conf.dist
-rw-r--r-- 1 root root 227 Aug 10 11:22 /etc/exim.conf.local
-rw-r--r-- 1 root root  95 Aug  3 17:03 /etc/exim.conf.localopts
-rw-r--r-- 1 root root 30K Feb 18 09:11 /etc/exim.conf.mailman2.dist
-rw-r--r-- 1 root root 30K Feb 18 09:11 /etc/exim.conf.mailman2.exiscan.dist

I would highly suggest advising to use WHM > Exim Configuration Editor > Advanced Editor in your guide, since otherwise you will have most people who do not have that file exist. Feel free to test this on a new machine to see the results similar to mine above.

[consultorpc]

Ok, i have updated the instructions on the original post.