UTF8: Cert namechecks always use a-label

[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 ce4edeb3d8c47bd5397593ff5505bb34083275e9..d446f6b67716c19932c4e29cf4f85d6f5f48d231 100644 (file)
--- a/doc/doc-txt/experimental-spec.txt
+++ b/doc/doc-txt/experimental-spec.txt
@@ -1276,7 +1276,66 @@ SMTPUTF8
 Internationalised mail name handling.
 RFCs 6530, 6533, 5890
 
+Compile with EXPERIMENTAL_INTERNATIONAL and libidn.
 
+New main config option smtputf8_advertise_hosts, default '*',
+a host list.  If this matches the sending host and
+accept_8bitmime is true (the default) then the ESMTP option
+SMTPUTF8 will be advertised.
+
+If the sender specifies the SMTPUTF8 option on a MAIL command
+international handling for the message is enabled and
+the expansion variable $message_smtputf8 will have value TRUE.
+
+The option allow_utf8_domains is set to true for this
+message. All DNS lookups are converted to a-label form
+whatever the setting of allow_utf8_domains.
+
+Both localparts and domain are maintained as the original
+utf8 form internally; any matching or regex use will
+require appropriate care.  Filenames created, eg. by
+the appendfile transport, will have utf8 name.
+
+Helo names sent by the smtp transport will have any utf8
+components expanded to a-label form.
+
+Any certificate name checks will be done using the a-label
+form of the name.
+
+Log lines and Received-by: header lines will aquire a "utf8"
+prefix on the protocol element, eg. utf8esmtp.
+
+New expansion operators:
+       ${utf8_domain_to_alabel:str}
+       ${utf8_domain_from_alabel:str}
+       ${utf8_localpart_to_alabel:str}
+       ${utf8_localpart_from_alabel:str}
+
+New "control = utf8_downconvert" ACL modifier,
+sets a flag requiring that addresses are converted to
+a-label form before smtp delivery, for use in a
+Message Submission Agent context.  Can also be
+phrased as "control = utf8_downconvert/1" and is
+mandatory.  The flag defaults to zero and can be cleared
+by "control = utf8_downconvert/0".  The value "-1"
+may also be used, to use a-label for only if the
+destination host does not support SMTPUTF8.
+
+If mua_wrapper is set, the utf8_downconvert control
+defaults to -1 (convert if needed).
+
+
+There is no explicit support for VRFY and EXPN.
+Configurations supporting these should inspect
+$smtp_command_argument for an SMTPUTF8 argument.
+
+There is no support for LMTP on Unix sockets.
+Using the "lmtp" protocol option on an smtp transport,
+for LMTP over TCP, should work as expected.
+
+Known issues:
+ - DSN unitext handling is not present
+ - no provision for converting logging from or to UTF-8
 
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