Spec docs for IDNA2008 support

[exim.git] / doc / doc-docbook / spec.xfpt

diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt
index 7d8b908f81a18c638d71408d9c85179518c65082..919b36a146d5260aa27baa6594e6dd31da39f13c 100644 (file)
--- a/doc/doc-docbook/spec.xfpt
+++ b/doc/doc-docbook/spec.xfpt
@@ -52,7 +52,7 @@
 .set I   "    "
 
 .macro copyyear
-2016
+2017
 .endmacro
 
 . /////////////////////////////////////////////////////////////////////////////
@@ -12257,7 +12257,7 @@ qualified host name. See also &$smtp_active_hostname$&.
        &$proxy_local_port$& &&&
        &$proxy_session$&
 These variables are only available when built with Proxy Protocol
-or Socks5 support
+or SOCKS5 support.
 For details see chapter &<<SECTproxyInbound>>&.
 
 .vitem &$prdr_requested$&
@@ -12607,6 +12607,13 @@ validating resolver (e.g. unbound, or bind with suitable configuration).
 If you have changed &%host_lookup_order%& so that &`bydns`& is not the first
 mechanism in the list, then this variable will be false.
 
+.new
+This requires that your system resolver library support EDNS0 (and that
+DNSSEC flags exist in the system headers).  If the resolver silently drops
+all EDNS0 options, then this will have no effect.  OpenBSD's asr resolver
+is known to currently ignore EDNS0, documented in CAVEATS of asr_run(3).
+.wen
+
 
 .vitem &$sender_host_name$&
 .vindex "&$sender_host_name$&"
@@ -14665,6 +14672,7 @@ record in the authoritative section is used instead.
 .option dns_use_edns0 main integer -1
 .cindex "DNS" "resolver options"
 .cindex "DNS" "EDNS0"
+.cindex "DNS" "OpenBSD
 If this option is set to a non-negative number then Exim will initialise the
 DNS resolver library to either use or not use EDNS0 extensions, overriding
 the system default. A value of 0 coerces EDNS0 off, a value of 1 coerces EDNS0
@@ -14672,6 +14680,12 @@ on.
 
 If the resolver library does not support EDNS0 then this option has no effect.
 
+.new
+OpenBSD's asr resolver routines are known to ignore the EDNS0 option; this
+means that DNSSEC will not work with Exim on that platform either, unless Exim
+is linked against an alternative DNS client library.
+.wen
+
 
 .option drop_cr main boolean false
 This is an obsolete option that is now a no-op. It used to affect the way Exim
@@ -16871,6 +16885,9 @@ generates any deliveries to files or pipes, or any new mail messages, the
 appropriate &%system_filter_..._transport%& option(s) must be set, to define
 which transports are to be used. Details of this facility are given in chapter
 &<<CHAPsystemfilter>>&.
+.new
+A forced expansion failure results in no filter operation.
+.wen
 
 
 .option system_filter_directory_transport main string&!! unset
@@ -28917,7 +28934,11 @@ message body.
 Cutthrough delivery is not supported via transport-filters or when DKIM signing
 of outgoing messages is done, because it sends data to the ultimate destination
 before the entire message has been received from the source.
-It is not supported for messages received with the SMTP PRDR option in use.
+It is not supported for messages received with the SMTP PRDR
+.new
+or CHUNKING
+.wen
+options in use.
 
 Should the ultimate destination system positively accept or reject the mail,
 a corresponding indication is given to the source system and nothing is queued.
@@ -29768,6 +29789,15 @@ to avoid doing it more than once per message.
 .cindex "&%verify%& ACL condition"
 This is a variation of the previous option, in which a modified address is
 verified as a sender.
+
+.new
+Note that '/' is legal in local-parts; if the address may have such
+(eg. is generated from the received message)
+they must be protected from the options parsing by doubling:
+.code
+verify = sender=${sg{${address:$h_sender:}}{/}{//}}
+.endd
+.wen
 .endlist
 
 
@@ -36033,7 +36063,7 @@ The latter can be disabled by turning off the &%outgoing_interface%& option.
 &%proxy%&: The internal (closest to the system running Exim) IP address
 of the proxy, tagged by PRX=, on the &"<="& line for a message accepted
 on a proxied connection
-or the &"=>"& line for a message delivered on a proxied connection..
+or the &"=>"& line for a message delivered on a proxied connection.
 See &<<SECTproxyInbound>>& for more information.
 .next
 .cindex "log" "incoming remote port"
@@ -37893,9 +37923,8 @@ lock will be lost at the instant of rename.
 .next
 .vindex "&$body_linecount$&"
 If you change the number of lines in the file, the value of
-&$body_linecount$&, which is stored in the -H file, will be incorrect. At
-present, this value is not used by Exim, but there is no guarantee that this
-will always be the case.
+&$body_linecount$&, which is stored in the -H file, will be incorrect and can
+cause incomplete transmission of messages or undeliverable messages.
 .next
 If the message is in MIME format, you must take care not to break it.
 .next
@@ -38524,6 +38553,13 @@ recorded in an ACL (example is below).
 Use of a proxy is enabled by setting the &%hosts_proxy%&
 main configuration option to a hostlist; connections from these
 hosts will use Proxy Protocol.
+Exim supports both version 1 and version 2 of the Proxy Protocol and
+automatically determines which version is in use.
+
+The Proxy Protocol header is the first data received on a TCP connection
+and is inserted before any TLS-on-connect handshake from the client; Exim
+negotiates TLS between Exim-as-server and the remote client, not between
+Exim and the proxy server.
 
 The following expansion variables are usable
 (&"internal"& and &"external"& here refer to the interfaces
@@ -38644,6 +38680,12 @@ Exim has support for Internationalised mail names.
 To include this it must be built with SUPPORT_I18N and the libidn library.
 Standards supported are RFCs 2060, 5890, 6530 and 6533.
 
+.new
+If Exim is built with SUPPORT_I18N_2008 (in addition to SUPPORT_I18N, not
+instead of it) then IDNA2008 is supported; this adds an extra library
+requirement, upon libidn2.
+.wen
+
 .section "MTA operations" SECTi18nMTA
 .cindex SMTPUTF8 "ESMTP option"
 The main configuration option &%smtputf8_advertise_hosts%& specifies