Dear All,
I am attempting to configure my server (exim-4.92.3) to ARC
(Authenticated Received Chain) sign and possibly also verify messages.
I already DKIM sign messages which verify on external receiving MTAs when
the sender address is in my local domain. The server also maintains a set
of distribution lists expanded from aliases. Some of the senders to these
distribution lists are outside my local domain which breaks DKIM
verification, which is why I want to try ARC signing.
I accept ARC is a new, experimental feature in EXIM but the documentation
in doc/experimental-spec.txt is very brief. The thing I really need is
some simple worked example configurations.
Ideally I just need to check whether an incoming message was for one of my
distribution lists and if so ARC sign it.
Currently I have tried this simple configuration,
remote_smtp:
driver = smtp
dkim_domain = $sender_address_domain
dkim_selector = selector3
dkim_private_key = /etc/exim/dkim/selector3.pem
dkim_canon = relaxed
EXPERIMENTAL_ARC=yes
arc_sign = $primary_hostname : selector3 : /etc/exim/dkim/selector3.pem
but exim fails to start with "Exim configuration error in line XXX"
"transport name missing"
where line XXX is the 'arc_sign = ' line.
What am I doing wrong?
Please help.
Thanks
Tom Crane
