Exim and sendmail compatibility

I’ve maintained a rather large mail cluster using the Exim mta .
Configuring an MTA is something that is a lot more complicated than one would expect, until you try it. I know Exim now, and aren’t really motivated at learning sendmail or postfix, so I tend to switch to exim as the default mta for any server I administer .

I just did some debugging where a Mojolicious application didn’t send out email, and it turned out the exim ‘sendmail’ compatibility wasn’t 100% compatible with sendmail’s sendmail …
( Long story short: first there was sendmail in every Unix. Then came postfix and exim, but because a lot of Unix utilities already was programmed to using sendmail ‘they’ [postfix and exim] made a sendmail binary/wrapper that accept the same options as sendmail )

Anyway after some debugging I noticed that it seemed like the perl Mail lib was default’ing to adding -t to sendmail . And I had a look in the exim documentation and noticed that they _do_ support -t, but as they wrote:

If the command has any arguments, they specify addresses to which the message is not to be delivered. That is, the argument addresses are removed from the recipients list obtained from the headers. This is compatible with Smail 3 and in accordance with the documented behaviour of several versions of Sendmail, as described in man pages on a number of operating systems (e.g. Solaris 8, IRIX 6.5, HP-UX 11). However, some versions of Sendmail add argument addresses to those obtained from the headers, and the O’Reilly Sendmail book documents it that way. Exim can be made to add argument addresses instead of subtracting them by setting the option extract_addresses_remove_arguments false.

soooo I tried adding

extract_addresses_remove_arguments = true

to exim.conf, and it seem to have solved the problem.