From 617d39327e65b7fccc41a12b4a5e2940d6327c9f Mon Sep 17 00:00:00 2001 From: Jeremy Harris Date: Fri, 2 Mar 2018 23:53:32 +0000 Subject: ARC initial implementation. Experimental. Bug 2162 --- doc/doc-txt/experimental-spec.txt | 47 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 47 insertions(+) (limited to 'doc/doc-txt/experimental-spec.txt') diff --git a/doc/doc-txt/experimental-spec.txt b/doc/doc-txt/experimental-spec.txt index d5140d58b..4ed6f2518 100644 --- a/doc/doc-txt/experimental-spec.txt +++ b/doc/doc-txt/experimental-spec.txt @@ -756,6 +756,53 @@ to your Local/Makefile. (Re-)build/install exim. exim -d should show Experimental_QUEUEFILE in the line "Support for:". +ARC support +----------- +Specification: https://tools.ietf.org/html/draft-ietf-dmarc-arc-protocol-11 +Note that this is not an RFC yet, so may change. + +ARC is intended to support the utility of SPF and DKIM in the presence of +intermediaries in the transmission path - forwarders and mailinglists - +by establishing a cryptographically-signed chain in headers. + +Normally one would only bother doing ARC-signing when functioning as +an intermediary. One might do verify for local destinations. + +ARC uses the notion of a "ADministrative Management Domain" (ADMD). +Described in RFC 5598 (section 2.3), this is essentially the set of +mail-handling systems that the mail transits. A label should be chosen to +identify the ADMD. Messages should be ARC-verified on entry to the ADMD, +and ARC-signed on exit from it. + + +Verification +-- +An ACL condition is provided to perform the "verifier actions" detailed +in section 6 of the above specification. It may be called from the DATA ACL +and succeeds if the result matches any of a given list. +It also records the highest ARC instance number (the chain size) +and verification result for later use in creating an Authentication-Results: +standard header. + + verify = arc/ none:fail:pass + + add_header = :at_start:${authresults {}} + + Note that it would be wise to strip incoming messages of A-R headers + that claim to be from our own . + +Receive log lines for an ARC pass will be tagged "ARC". + + +Signing +-- +arc_sign = : : +An option on the smtp transport, which constructs and prepends to the message +an ARC set of headers. The textually-first Authentication-Results: header +is used as a basis (you must have added one on entry to the ADMD). + + + -------------------------------------------------------------- End of file -------------------------------------------------------------- -- cgit v1.2.3