Docs: tweak ARC description

[exim.git] / doc / doc-txt / experimental-spec.txt

diff --git a/doc/doc-txt/experimental-spec.txt b/doc/doc-txt/experimental-spec.txt
index 43f14237bc502097d9dae4ab7ae7ddf6e3494c8d..49935fb401e2a0523c1e2c743371da536f5c8ce4 100644 (file)
--- a/doc/doc-txt/experimental-spec.txt
+++ b/doc/doc-txt/experimental-spec.txt
@@ -447,11 +447,19 @@ dmarc_history_file  Defines the location of a file to log results
                     directory of this file is writable by the user
                     exim runs as.
 
-dmarc_forensic_sender The email address to use when sending a
+dmarc_forensic_sender Alternate email address to use when sending a
                     forensic report detailing alignment failures
                     if a sender domain's dmarc record specifies it
                     and you have configured Exim to send them.
-                    Default: do-not-reply@$default_hostname
+
+                   If set, this is expanded and used for the
+                   From: header line; the address is extracted
+                   from it and used for the envelope from.
+                   If not set, the From: header is expanded from
+                   the dsn_from option, and <> is used for the
+                   envelope from.
+
+                    Default: unset.
 
 
 3. By default, the DMARC processing will run for any remote,
@@ -709,6 +717,8 @@ an external directory retaining the exim spool format.
 
 The spool files can then be processed by external processes and then
 requeued into exim spool directories for final delivery.
+However, note carefully the warnings in the main documentation on
+qpool file formats.
 
 The motivation/inspiration for the transport is to allow external
 processes to access email queued by exim and have access to all the
@@ -793,7 +803,7 @@ standard header.
        Note that it would be wise to strip incoming messages of A-R headers
        that claim to be from our own <admd-identifier>.
 
-There are three new variables: $arc_state, $arc_state_reason, $arc_domains:
+There are four new variables:
 
   $arc_state           One of pass, fail, none
   $arc_state_reason    (if fail, why)
@@ -881,12 +891,15 @@ The Exim implementation includes
 
 Differences from spec:
 - we support upgrading the requirement for REQUIRETLS, including adding
-  it from cold, withing an MTA.  The spec only define the sourcing MUA
+  it from cold, within an MTA.  The spec only define the sourcing MUA
   as being able to source the requirement, and makes no mention of upgrade.
 - No support is coded for the RequireTLS header (which can be used
-  to annul DANE and/or STS policiy). [can this be done in ACL?]
+  to annul DANE and/or STS policiy). [this can _almost_ be done in
+  transport option expansions, but not quite: it requires tha DANE-present
+  but STARTTLS-failing targets fallback to cleartext, which current DANE
+  coding specifically blocks]
 
-Note that REQUIRETLS is only advertised once a TLS connection is acheived
+Note that REQUIRETLS is only advertised once a TLS connection is achieved
 (in contrast to STARTTLS).  If you want to check the advertising, do something
 like "swaks -s 127.0.0.1 -tls -q HELO".