Q0431

`Navigation(siblings)`_

How do I configure Exim to allow arbitrary extensions in local parts, of the form +extension?

Add this pre-condition to the relevant router:

local_part_suffix = +*

If you want the extensions to be optional, also add the option

local_part_suffix_optional

When the router runs, $local_part contains the local part with the extension removed, and the extension (if any) is in $local_part_suffix. If you have set check_local_user, the test is carried out after the extension is removed.