Hello,
I am interested in developing a content filtering application, and I
want to know which is the best way of passing messages to a third
party application, from Exim.
I've looked over ACLs and local_scan API. As far as I can tell, there
isn't a suitable way of using ACLs with third party applications, but
I may be wrong.
As about local_scan, it isn't yet an option for my case, because it
needs a specially compiled version of Exim.
I've checked amavisd-new (which has some documentation for interfacing
with Exim), and I noticed that the standard configuration implies
changing the routers in Exim configuration file. This seems to be the
best choice, but there is a downside: a reject action from the third
party application would result in a bounce, which is not desired.
For the same project, I've made some research regarding other MTAs.
For instance, Postfix offers three types of interfacing with a third
party application: before-queue [1], after-queue [2], and lately it
offers a compatible milter interface [3].
The after-queue option has the same downside, a reject action is
generating a bounce, while the first and the third work correctly.
Since the local_scan API in its current form is out of the question,
what I need to know is if there is any Exim capabilities similar to
Postfix before-queue content filtering.
Thank you in advance.
References:
[1] -
http://www.postfix.org/SMTPD_PROXY_README.html
[2] -
http://www.postfix.org/FILTER_README.html
[3] -
http://www.postfix.org/MILTER_README.html
--
Claudiu Dragalina-Paraipan
