doc/admin.texi              |   8 ++++++--
 doc/building.texi           |   7 ++++++-
 doc/call.texi               |   8 ++++----
 doc/cfg/index.texi          |  10 +++++-----
 doc/cfg/neigh.texi          |   2 +-
 doc/cmd/nncp-toss.texi      |   2 +-
 doc/download.texi           |   4 ++++
 doc/index.texi              |  28 ++++++++++++++--------------
 doc/install.texi            |  16 ++++++++--------
 doc/integration.texi        |  12 ++++++------
 doc/multicast.texi          |   2 +-
 doc/news.ru.texi            |  62 ++++++++---------------------------------------------
 doc/news.texi               |  61 +++++++----------------------------------------------
 doc/nncp.html.do            |   1 -
 doc/nncp.info.do            |  12 +++++++++++-
 doc/pkt/index.texi          |   6 +++---
 doc/russian.texi            |   6 +++---
 doc/usecases.ru.texi        | 118 ++++++++++++++++++++++++++++++++++++++++++++++-------
 doc/usecases.texi           | 116 ++++++++++++++++++++++++++++++++++++++++++++++-------
 makedist.sh                 |   6 +++---
 ports/nncp/Makefile         |   2 +-
 src/cmd/nncp-cfgnew/main.go |   2 +-
 src/go.sum                  |   2 --
 src/mcd.go                  |  16 ++++++++++------
 src/nncp.go                 |   2 +-

diff --git a/doc/admin.texi b/doc/admin.texi
index 510f0ffc4e901d8365b714afaac2366aec2d039eb68ec86f7c75ef48d8f7c506..05856e383eccfb932b6570ef2352a875ea36307340e698ff98f6f269e9db390f 100644
--- a/doc/admin.texi
+++ b/doc/admin.texi
@@ -20,6 +20,10 @@
     Partly transferred files are stored with @file{.part} suffix. And
     possibly they also require cleanup if they are completely lost.
 
+    It can contain @file{.nock} files: fully downloaded, but still not
+    checksummed. Can be checksummed (with @file{.nock} extension removing)
+    with @command{nncp-check -nock}.
+
     Also it can contain @file{.seen} files, that should be cleaned too
     from time to time.
 
@@ -60,8 +64,8 @@ @end example
 
 @item
     Possibly long running @ref{nncp-daemon}, @ref{nncp-caller},
-    @ref{nncp-toss} daemons. As all software, they can fail and you
-    should place them under some supervisor control.
+    @ref{nncp-toss}, @ref{nncp-check} daemons. As all software, they can
+    fail and you should place them under some supervisor control.
 
     For example you can use @url{http://cr.yp.to/daemontools.html,
     daemontools} for that task to run them under probably existing
diff --git a/doc/building.texi b/doc/building.texi
index 83f0a52f97c27dea31f938f908e6476cef7524d4cf4ebffdb9fddee37ca182f3..dbb6fecf32f64a599f12339bbad27a24006b65c191cc07c2e3e868e80be24455 100644
--- a/doc/building.texi
+++ b/doc/building.texi
@@ -17,8 +17,13 @@ $ gpg --verify nncp-@value{VERSION}.tar.xz.sig nncp-@value{VERSION}.tar.xz
 $ xz --decompress --stdout nncp-@value{VERSION}.tar.xz | tar xf -
 $ cd nncp-@value{VERSION}
 $ redo all
-# look for bin/nncp-* binaries (and possibly hjson-cli one)
 @end example
+
+After that you should get various @command{bin/nncp-*} binaries and
+@command{bin/hjson-cli} command (only for your convenience, not
+necessary installation). Documentation for example for
+@command{nncp-bundle} command can be get with
+@command{info doc/nncp.info -n nncp-bundle}.
 
 It uses @url{http://cr.yp.to/redo.html, redo} build system for that
 examples. You can use either dozen of various implementations, or at
diff --git a/doc/call.texi b/doc/call.texi
index 765ef7132ae43bea346cbbe04b2aabae1ddd303700ba2e70383805aff05b6984..b27c61422429bcdbc971a621c3c38d24d16204d8c56c16ef713c589efdd7d61d 100644
--- a/doc/call.texi
+++ b/doc/call.texi
@@ -14,7 +14,7 @@         nice: PRIORITY+10
 
         autotoss: true
         autotoss-doseen: true
-    },
+    }
     {
         cron: "30 * * * SAT,SUN"
         onlinedeadline: 1800
@@ -22,18 +22,18 @@         maxonlinetime: 1750
         nice: NORMAL
         rxrate: 10
         txrate: 20
-    },
+    }
     {
         cron: "0 * * * SAT,SUN"
         xx: rx
         addr: lan
-    },
+    }
     {
         cron: "*/5 * * * * * *"
         when-tx-exists: true
         nock: true
         mcd-ignore: true
-    },
+    }
 ]
 @end verbatim
 
diff --git a/doc/cfg/index.texi b/doc/cfg/index.texi
index 2eb251879b2dab81ca7c7ea3cf300e1d0c3f535ee6d5e7d914287cbf694c1b38..7fd71d72c999a99349fe968f909b4216411667b8e731c4b6268de1c6a320c868 100644
--- a/doc/cfg/index.texi
+++ b/doc/cfg/index.texi
@@ -44,11 +44,11 @@
 Whole configuration file can be separated on five sections:
 
 @menu
-* General options: CfgGeneral.
-* Self-node keypairs: CfgSelf.
-* Notifications: CfgNotify.
-* Neighbours: CfgNeigh.
-* Areas: CfgAreas.
+* General options: CfgGeneral
+* Self-node keypairs: CfgSelf
+* Notifications: CfgNotify
+* Neighbours: CfgNeigh
+* Areas: CfgAreas
 
 You can optionally convert it to directory layout
 * Configuration directory::
diff --git a/doc/cfg/neigh.texi b/doc/cfg/neigh.texi
index 2acbc46e2629292bcc4e46f318b932bf2cc45c2cb8fa5b3a6cfafae65fa8bf4b..171ceaee62a5f6abebaa8b841f7093078e99e62ad480b0bf645aaf3073e7daa1 100644
--- a/doc/cfg/neigh.texi
+++ b/doc/cfg/neigh.texi
@@ -32,7 +32,7 @@     }
     calls: [
       {
         cron: "*/2 * * * *"
-      },
+      }
     ]
   }
   bob: {
diff --git a/doc/cmd/nncp-toss.texi b/doc/cmd/nncp-toss.texi
index 62db52e63eb2d9af6ff5166c2bade2b01f580a4af7baf16e36bd95699796685b..2d359a4f88d33a26a111b45b9f9cf303a6fc04e7463e92078887dbc66179566a 100644
--- a/doc/cmd/nncp-toss.texi
+++ b/doc/cmd/nncp-toss.texi
@@ -29,4 +29,4 @@ inbound packets that has been already seen, processed and tossed. This
 is helpful to prevent duplicates.
 
 @option{-nofile}, @option{-nofreq}, @option{-noexec}, @option{-notrns},
-@option{-noarea} options allow to disable any kind of packet types processing.
+@option{-noarea} options allow disabling any kind of packet types processing.
diff --git a/doc/download.texi b/doc/download.texi
index 7fe15f52af74ea39e1b37c0d5f7f16e44439ed62cc041cf9114679a05327f1ac..0dc6b66e61436eb813186ce0073183108499e2855e267deab728882f30509088 100644
--- a/doc/download.texi
+++ b/doc/download.texi
@@ -28,6 +28,10 @@
 @multitable {XXXXX} {XXXX-XX-XX} {XXXX KiB} {link sign} {xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx}
 @headitem Version @tab Date @tab Size @tab Tarball @tab SHA256 checksum
 
+@item @ref{Release 7_3_2, 7.3.2} @tab 2021-07-12 @tab 1141 KiB
+@tab @url{download/nncp-7.3.2.tar.xz, link} @url{download/nncp-7.3.2.tar.xz.sig, sign}
+@tab @code{65F6A230 04189D3F 307D160C AE97F99A 620DDA23 52821652 15DDC946 F6CC4B7F}
+
 @item @ref{Release 7_3_1, 7.3.1} @tab 2021-07-11 @tab 1142 KiB
 @tab @url{download/nncp-7.3.1.tar.xz, link} @url{download/nncp-7.3.1.tar.xz.sig, sign}
 @tab @code{8611DC6A 3EAC7FFA A6A1C688 2073AB4D A4E93D36 C864F050 C5F880FE 10FCFC46}
diff --git a/doc/index.texi b/doc/index.texi
index dbb278842e04af91b3c7f3044c5e173fa24b1066e973f71c373823d40fe7bcc3..b3a751b41ca910a79fd106e2a7cf2e5b1108bb71b0000e122efdfa35817ce9b7 100644
--- a/doc/index.texi
+++ b/doc/index.texi
@@ -17,7 +17,7 @@ @end quotation
 @end copying
 
 @node Top
-@top
+@top NNCP
 
 @verbatiminclude pedro.txt
 
@@ -39,27 +39,27 @@ * Comparison::
 * Use cases::
 * Workflow::
 * News::
-* Информация на русском: Русский.
+* Информация на русском: Русский
 * Installation::
 * Configuration::
-* Call configuration: Call.
-* Multicast areas: Multicast.
+* Call configuration: Call
+* Multicast areas: Multicast
 * Integration::
 * Commands::
 * Administration::
 * Niceness::
-* Chunked files: Chunked.
+* Chunked files: Chunked
 * Bundles::
-* Spool directory: Spool.
-* Log format: Log.
-* Packet format: Packet.
-* Merkle Tree Hashing: MTH.
-* Sync protocol: Sync.
-* MultiCast Discovery: MCD.
-* EBlob format: EBlob.
+* Spool directory: Spool
+* Log format: Log
+* Packet format: Packet
+* Merkle Tree Hashing: MTH
+* Sync protocol: Sync
+* MultiCast Discovery: MCD
+* EBlob format: EBlob
 * Thanks::
-* Contacts and feedback: Contacts.
-* Copying conditions: Copying.
+* Contacts and feedback: Contacts
+* Copying conditions: Copying
 @end menu
 
 @include comparison.texi
diff --git a/doc/install.texi b/doc/install.texi
index a81b143b3efc76a8b468ffd9358138cc3fe4151377274236fcb20320b149e84a..831fc8e1f2d972b00e143d45991d17c1e2ce405df4531c6f99e7d03cc6f951ba 100644
--- a/doc/install.texi
+++ b/doc/install.texi
@@ -14,10 +14,10 @@
 NNCP should run on any POSIX-compatible operating system.
 
 NNCP is written on @url{https://golang.org/, Go} programming language
-and you have to install Go compiler 1.13+ version. @command{Make} (BSD
-and GNU versions are fine) is recommended for convenient building.
-@url{https://www.gnu.org/software/texinfo/, Texinfo} is used for
-building documentation (although tarballs already include it).
+and you have to install Go compiler 1.13+ version.
+@url{http://cr.yp.to/redo.html, redo} build system is recommended for
+convenience. @url{https://www.gnu.org/software/texinfo/, Texinfo} is
+used for building documentation (although tarballs already include it).
 
 In general you must get @ref{Tarballs, the tarball}, check its
 @ref{Integrity, integrity and authenticity} and run @command{make}.
@@ -25,10 +25,10 @@ Look for general and platform-specific @ref{Build-instructions, build
 instructions}.
 
 @menu
-* Prepared tarballs: Tarballs.
-* Tarballs integrity check: Integrity.
-* Build instructions: Build-instructions.
-* Development source code: Sources.
+* Prepared tarballs: Tarballs
+* Tarballs integrity check: Integrity
+* Build instructions: Build-instructions
+* Development source code: Sources
 @end menu
 
 @include download.texi
diff --git a/doc/integration.texi b/doc/integration.texi
index 8772ca91622de806a2d42eb7899db0f63312d19f3276534bd1d3462a7a487317..6fb5fdc750883eaf130e39b325ea88a254b44598705d9e3bd06dd2ea9f124b7c 100644
--- a/doc/integration.texi
+++ b/doc/integration.texi
@@ -5,15 +5,15 @@ Here is some examples of how you can solve popular tasks with NNCP,
 making them store-and-forward friendly.
 
 @menu
-* Index files for freqing: FreqIndex.
+* Index files for freqing: FreqIndex
 * Postfix::
 * Exim::
-* Web feeds: Feeds.
-* Web pages: WARCs.
-* BitTorrent and huge files: BitTorrent.
-* Downloading service: DownloadService.
+* Web feeds: Feeds
+* Web pages: WARCs
+* BitTorrent and huge files: BitTorrent
+* Downloading service: DownloadService
 * Git::
-* Multimedia streaming: Multimedia.
+* Multimedia streaming: Multimedia
 @end menu
 
 @node FreqIndex
diff --git a/doc/multicast.texi b/doc/multicast.texi
index 8b02ddc66b67e3c6fbf8f8ea30291d651771d654ee1b8994c061f93516b71100..e7e07e5b1189a5b5c5b3637d28d7e7812050b70624e2555fdec9b3dbdbbf2c29 100644
--- a/doc/multicast.texi
+++ b/doc/multicast.texi
@@ -10,7 +10,7 @@ @anchor{Area}
 Each multicast group is identified by so-called @strong{area}. Area
 consists of private/public Curve25519 keypairs for @ref{Encrypted area,
 packets encryption}, identity (BLAKE2b-256 hash of the public key) and
-possible subscribers.
+possible subscribers. Areas are created with @ref{nncp-cfgnew} command.
 
 You can make either file or exec transmissions to the areas. Those
 ordinary file/exec packets are double wrapped in:
diff --git a/doc/news.ru.texi b/doc/news.ru.texi
index 4ca22df2f0c2c7b4542e20e3c35aa33820bc6bdedd94279a638e5085394bcde1..c83257dd6094d1b60e39fb7fa2a601ccc62ea64cf88ded1be01e4b17982d0d77 100644
--- a/doc/news.ru.texi
+++ b/doc/news.ru.texi
@@ -1,59 +1,15 @@
 @node Новости
 @section Новости
 
-@menu
-* Релиз 7.3.2::
-* Релиз 7.3.1::
-* Релиз 7.3.0::
-* Релиз 7.2.1::
-* Релиз 7.2.0::
-* Релиз 7.1.1::
-* Релиз 7.1.0::
-* Релиз 7.0.0::
-* Релиз 6.6.0::
-* Релиз 6.5.0::
-* Релиз 6.4.0::
-* Релиз 6.3.0::
-* Релиз 6.2.1::
-* Релиз 6.2.0::
-* Релиз 6.1.0::
-* Релиз 6.0.0::
-* Релиз 5.6.0::
-* Релиз 5.5.1::
-* Релиз 5.5.0::
-* Релиз 5.4.1::
-* Релиз 5.4.0::
-* Релиз 5.3.3::
-* Релиз 5.3.2::
-* Релиз 5.3.1::
-* Релиз 5.3.0::
-* Релиз 5.2.1::
-* Релиз 5.2.0::
-* Релиз 5.1.2::
-* Релиз 5.1.1::
-* Релиз 5.1.0::
-* Релиз 5.0.0::
-* Релиз 4.1::
-* Релиз 4.0::
-* Релиз 3.4::
-* Релиз 3.3::
-* Релиз 3.2::
-* Релиз 3.1::
-* Релиз 3.0::
-* Релиз 2.0::
-* Релиз 1.0::
-* Релиз 0.12::
-* Релиз 0.11::
-* Релиз 0.10::
-* Релиз 0.9::
-* Релиз 0.8::
-* Релиз 0.7::
-* Релиз 0.6::
-* Релиз 0.5::
-* Релиз 0.4::
-* Релиз 0.3::
-* Релиз 0.2::
-@end menu
+@node Релиз 7.4.0
+@subsection Релиз 7.4.0
+@itemize
+
+@item
+Исправлена работоспособность MCD при одновременном использовании
+@command{nncp-daemon} и @command{nncp-caller}.
+
+@end itemize
 
 @node Релиз 7.3.2
 @subsection Релиз 7.3.2
diff --git a/doc/news.texi b/doc/news.texi
index 378b2054b49a29ded9f3d60ad62721bff2769e5fd052368a66d1e2ad93c26579..750383807c7249660bf1b2c43592f7fd7bd23e152ba782dfa5a8947c1bba8d85 100644
--- a/doc/news.texi
+++ b/doc/news.texi
@@ -3,59 +3,14 @@ @unnumbered News
 
 See also this page @ref{Новости, on russian}.
 
-@menu
-* Release 7.3.2: Release 7_3_2.
-* Release 7.3.1: Release 7_3_1.
-* Release 7.3.0: Release 7_3_0.
-* Release 7.2.1: Release 7_2_1.
-* Release 7.2.0: Release 7_2_0.
-* Release 7.1.1: Release 7_1_1.
-* Release 7.1.0: Release 7_1_0.
-* Release 7.0.0: Release 7_0_0.
-* Release 6.6.0: Release 6_6_0.
-* Release 6.5.0: Release 6_5_0.
-* Release 6.4.0: Release 6_4_0.
-* Release 6.3.0: Release 6_3_0.
-* Release 6.2.1: Release 6_2_1.
-* Release 6.2.0: Release 6_2_0.
-* Release 6.1.0: Release 6_1_0.
-* Release 6.0.0: Release 6_0_0.
-* Release 5.6.0: Release 5_6_0.
-* Release 5.5.1: Release 5_5_1.
-* Release 5.5.0: Release 5_5_0.
-* Release 5.4.1: Release 5_4_1.
-* Release 5.4.0: Release 5_4_0.
-* Release 5.3.3: Release 5_3_3.
-* Release 5.3.2: Release 5_3_2.
-* Release 5.3.1: Release 5_3_1.
-* Release 5.3.0: Release 5_3_0.
-* Release 5.2.1: Release 5_2_1.
-* Release 5.2.0: Release 5_2_0.
-* Release 5.1.2: Release 5_1_2.
-* Release 5.1.1: Release 5_1_1.
-* Release 5.1.0: Release 5_1_0.
-* Release 5.0.0: Release 5_0_0.
-* Release 4.1: Release 4_1.
-* Release 4.0: Release 4_0.
-* Release 3.4: Release 3_4.
-* Release 3.3: Release 3_3.
-* Release 3.2: Release 3_2.
-* Release 3.1: Release 3_1.
-* Release 3.0: Release 3_0.
-* Release 2.0: Release 2_0.
-* Release 1.0: Release 1_0.
-* Release 0.12: Release 0_12.
-* Release 0.11: Release 0_11.
-* Release 0.10: Release 0_10.
-* Release 0.9: Release 0_9.
-* Release 0.8: Release 0_8.
-* Release 0.7: Release 0_7.
-* Release 0.6: Release 0_6.
-* Release 0.5: Release 0_5.
-* Release 0.4: Release 0_4.
-* Release 0.3: Release 0_3.
-* Release 0.2: Release 0_2.
-@end menu
+@node Release 7_4_0
+@section Release 7.4.0
+@itemize
+
+@item
+Fixed simultaneous @command{nncp-daemon} and @command{nncp-caller} MCD work.
+
+@end itemize
 
 @node Release 7_3_2
 @section Release 7.3.2
diff --git a/doc/nncp.html.do b/doc/nncp.html.do
index a246272b64115dbfbfbaa53270fee68a4923d0180f6be1fe3eb80401823bdcde..cc247f5881c5008cb58c356518813cea89f0f7aa6a8d39cc653ce4d2ac8b74f7 100644
--- a/doc/nncp.html.do
+++ b/doc/nncp.html.do
@@ -3,6 +3,5 @@ MAKEINFO_OPTS="$MAKEINFO_OPTS --html --css-include style.css"
 MAKEINFO_OPTS="$MAKEINFO_OPTS --set-customization-variable FORMAT_MENU=menu"
 MAKEINFO_OPTS="$MAKEINFO_OPTS --set-customization-variable SHOW_TITLE=0"
 MAKEINFO_OPTS="$MAKEINFO_OPTS --set-customization-variable DATE_IN_HEADER=1"
-MAKEINFO_OPTS="$MAKEINFO_OPTS --set-customization-variable TOP_NODE_UP_URL=index.html"
 MAKEINFO_OPTS="$MAKEINFO_OPTS" . nncp.info.do
 cp -r .well-known $3
diff --git a/doc/nncp.info.do b/doc/nncp.info.do
index bdffdd972d972af3c3614b28b4d58a3845434a1d8ff733d1107d6731200c494a..ffbb9bcaf49f9cee291b6939fec2f067bcb2903d592f6f1a1837ee1ca5bcfac1 100644
--- a/doc/nncp.info.do
+++ b/doc/nncp.info.do
@@ -1,8 +1,18 @@
-redo-ifchange ../config ../VERSION *.texi sp.plantuml.txt pedro.txt
+redo-ifchange \
+    ../config \
+    ../VERSION \
+    *.texi \
+    cfg/*.texi \
+    cmd/*.texi \
+    pkt/*.texi \
+    sp.plantuml.txt \
+    pedro.txt
 . ../config
 ${MAKEINFO:-makeinfo} \
     -D "VERSION `cat ../VERSION`" \
     $MAKEINFO_OPTS \
+    --set-customization-variable SECTION_NAME_IN_TITLE=1 \
+    --set-customization-variable TREE_TRANSFORMATIONS=complete_tree_nodes_menus \
     --set-customization-variable CLOSE_QUOTE_SYMBOL=\" \
     --set-customization-variable OPEN_QUOTE_SYMBOL=\" \
     --output $3 index.texi
diff --git a/doc/pkt/index.texi b/doc/pkt/index.texi
index 92760a309478b57e12c754a463cd866154a24402ac22a58e853eda38ec28621f..863e4c0a1d8012472be3fdd70a0a60a7cbfe319f22ee8cc6968aad78b8606078 100644
--- a/doc/pkt/index.texi
+++ b/doc/pkt/index.texi
@@ -5,9 +5,9 @@ All packets are
 @url{https://tools.ietf.org/html/rfc4506, XDR}-encoded structures.
 
 @menu
-* Plain packet: Plain.
-* Encrypted packet: Encrypted.
-* Encrypted area packet: Encrypted area.
+* Plain packet: Plain
+* Encrypted packet: Encrypted
+* Encrypted area packet: Encrypted area
 @end menu
 
 @include pkt/plain.texi
diff --git a/doc/russian.texi b/doc/russian.texi
index 2feeed7badffb1b52f00cb0b46b849862a76840816f54040a473ed88f6fcb1a9..af691b07093a6afd7ed07988ab30e8a3946d6d9c87ecead5416e9e7f323c7282 100644
--- a/doc/russian.texi
+++ b/doc/russian.texi
@@ -2,9 +2,9 @@ @node Русский
 @unnumbered Информация на русском
 
 @menu
-* Подробнее об утилитах NNCP: Об утилитах.
-* Сравнение с существующими решениями: Сравнение.
-* Сценарии использования: Сценарии.
+* Подробнее об утилитах NNCP: Об утилитах
+* Сравнение с существующими решениями: Сравнение
+* Сценарии использования: Сценарии
 * Новости::
 @end menu
 
diff --git a/doc/usecases.ru.texi b/doc/usecases.ru.texi
index a3534f6cbda4d5d43696f74bdce089c24d927eb81e0e1a236e042731135303f9..2c614cb1b0a32c492541731ca4a0f4d5c3f07d3a20d175329109997b4457f57d 100644
--- a/doc/usecases.ru.texi
+++ b/doc/usecases.ru.texi
@@ -2,18 +2,19 @@ @node Сценарии
 @section Сценарии использования
 
 @menu
-* Доступность почтового сервера время от времени: UsecaseMailRU.
-* Легковесная и быстрая замена POP3/IMAP4: UsecasePOPRU.
-* Ненадёжный/дорогой канал связи: UsecaseUnreliableRU.
-* Медленная/дорогая связь для больших объёмов данных, плохой QoS: UsecaseQoSRU.
-* Экстремальные наземные окружающие условия, нет связи: UsecaseNoLinkRU.
-* Односторонняя широковещательная связь: UsecaseBroadcastRU.
-* Спутниковые каналы связи: UsecaseSatelliteLinksRU.
-* Частные, изолированные MitM/Sybil-устойчивые сети: UsecaseF2FRU.
-* Высоко защищённые изолированные компьютеры с воздушным зазором: UsecaseAirgapRU.
-* Обход сетевой цензуры, здоровье: UsecaseCensorRU.
-* Разведка, шпионаж, тайная агентура: UsecaseSpyRU.
-* Дешёвая ночная связь: UsecaseCallerRU.
+* Доступность почтового сервера время от времени: UsecaseMailRU
+* Легковесная и быстрая замена POP3/IMAP4: UsecasePOPRU
+* Ненадёжный/дорогой канал связи: UsecaseUnreliableRU
+* Медленная/дорогая связь для больших объёмов данных, плохой QoS: UsecaseQoSRU
+* Экстремальные наземные окружающие условия, нет связи: UsecaseNoLinkRU
+* Односторонняя широковещательная связь: UsecaseBroadcastRU
+* Спутниковые каналы связи: UsecaseSatelliteLinksRU
+* Частные, изолированные MitM/Sybil-устойчивые сети: UsecaseF2FRU
+* Высоко защищённые изолированные компьютеры с воздушным зазором: UsecaseAirgapRU
+* Обход сетевой цензуры, здоровье: UsecaseCensorRU
+* Разведка, шпионаж, тайная агентура: UsecaseSpyRU
+* Дешёвая ночная связь: UsecaseCallerRU
+* Мультивещательная flooding рассылка: UsecaseMulticastRU
 @end menu
 
 @node UsecaseMailRU
@@ -257,6 +258,9 @@ из конфигурационного файла), послать все связанные с ним исходящие
 пакеты и получить от него. Все прерванные передачи будут автоматически
 возобновлены.
 
+А наличие возможности @ref{MCD, multicast обнаружения} участников сети в
+IPv6 сетях позволяет вообще не возиться с заданием сетевых адресов.
+
 @node UsecaseAirgapRU
 @subsection Высокозащищённые изолированные компьютеры с воздушным зазором
 
@@ -393,21 +397,105 @@         cron: "*/1 * * * *"
         addr: lan
         nice: MAX
         onlinedeadline: 3600
-      },
+      }
       {
         cron: "*/10 * * * *"
         addr: wan
         nice: PRIORITY
         xx: rx
-      },
+      }
       {
         cron: "*/1 0-7 * * *"
         addr: wan
         nice: BULK
         onlinedeadline: 3600
         maxonlinetime: 3600
-      },
+      }
     ]
   }
 }
 @end verbatim
+
+@node UsecaseMulticastRU
+@subsection Мультивещательная flooding рассылка
+
+Необходимо разослать одно и то же почтовое сообщение или файл многим
+участникам? Например обновления какой либо программы, списка участников
+сети или доступных файлов? Но при этом вы не соединены лично с каждым из
+них:
+
+@verbatim
+   A-------->E---->F    A <-> B C E
+  / \        |\    ^    C <-> H J
+ /   \       |  \  |    E <-> D F G
+v     v      v    \v    D <-> G
+B     C      D---->G    J <-> K
+     / \     ^    /     K <-> D G
+    /   \    |   /
+   v     v   v  /
+   H     J<->K<-
+@end verbatim
+
+В NNCP есть особые @ref{Multicast, мультивещательные} форматы пакетов
+позволяющие организовывать эффективную передачу одно единственного
+пакета сразу нескольким получателям (flooding алгоритм). @strong{A}
+отправляет пакет трём получателям. @strong{C} в свою очередь отсылает
+ещё двум, а @strong{E} трём. Некоторые участники сети получат несколько
+копий одного и того же пакета, как например @strong{D}, @strong{J},
+@strong{G}, @strong{F}, но копии будут просто проигнорированы. Если
+@strong{B} отошлёт пакет единственному ему известному @strong{A}, то
+этот пакет распространится по всей сети подписантов широковещательной
+зоны и дальше.
+
+Более того, мультивещательные пакеты зашифрованы и для прочтения требуют
+знание ключей. Но это не мешает их обрабатывать для дальнейшей пересылки!
+Кроме того, совершенно не обязательно знать ключи отправителя. Таким
+образом можно создать эхоконференцию для передачи файлов или команд
+(например доставки почтовых сообщений).
+
+Создаём ключи для мультивещательной зоны:
+
+@example
+$ nncp-cfgnew -area filelists -nocomments
+areas: @{
+  filelists: @{
+    id: TOU5TKOW4JBIZJBX63D4776C72FMWDAUAUSZNJX4DFOITVYQ5ZQA
+    pub: DSHL5O6BK2R3QKJAIJ7BC4UIGE73EC2LJPOV3VTS44KYOTUQYZLA
+    prv: AYD5FAA4GDDSAD5N65NJLLFS6TG2NSPQ46KAQO5U722JLVG34SOQ
+  @}
+@}
+@end example
+
+и отправляем ключевую пару всем кто может и хочет читать данную зону.
+Посредникам, готовым участвовать в переотправке пакетов подписантам, но
+которым не стоит "читать" пакеты, достаточно отправить только
+идентификатор зоны. Например @strong{A} добавляет себе в конфигурацию:
+
+@example
+areas: @{
+  filelists: @{
+    id: TOU...
+    pub: DSH...
+    prv: AYD...
+    subs: ["B", "C", "E"]
+    incoming: /home/A/areas/filelists
+  @}
+@end example
+
+а @strong{E}, являющимся (как было решено) просто посредником:
+
+@example
+areas: @{
+  filelists: @{
+    id: TOU...
+    subs: ["D", "F", "G"]
+  @}
+@end example
+
+После распространения знания о @code{filelists} мультивещательной зоне
+можно обмениваться @ref{FreqIndex, списками файлов}:
+
+@example
+$ nncp-file tree-of-A-20210715.txt.zst area:filelists:
+$ nncp-toss -node self
+@end example
diff --git a/doc/usecases.texi b/doc/usecases.texi
index 4bd8f5c48a9ada63a6f5274b28e7c10a9bd36f5c61c63f99c2d5e470df244ef7..84a62a7a8c1679ec77a52251854909a7d375c17a0b565e9dc8c6c28176b35bcf 100644
--- a/doc/usecases.texi
+++ b/doc/usecases.texi
@@ -4,18 +4,19 @@
 See also this page @ref{Сценарии, on russian}.
 
 @menu
-* Occasional connection to mail server: UsecaseMail.
-* Lightweight fast POP3/IMAP4 replacement: UsecasePOP.
-* Unreliable/expensive communication link: UsecaseUnreliable.
-* Slow/expensive link for high-volume data, bad QoS: UsecaseQoS.
-* Extreme terrestrial environments, no link: UsecaseNoLink.
-* One-way broadcasting communications: UsecaseBroadcast.
-* Satellite links: UsecaseSatelliteLinks.
-* Private, isolated MitM/Sybil-resistant networks: UsecaseF2F.
-* Highly secure isolated air-gap computers: UsecaseAirgap.
-* Network censorship bypassing, health: UsecaseCensor.
-* Reconnaissance, spying, intelligence, covert agents: UsecaseSpy.
-* Cheap night transfers: UsecaseCaller.
+* Occasional connection to mail server: UsecaseMail
+* Lightweight fast POP3/IMAP4 replacement: UsecasePOP
+* Unreliable/expensive communication link: UsecaseUnreliable
+* Slow/expensive link for high-volume data, bad QoS: UsecaseQoS
+* Extreme terrestrial environments, no link: UsecaseNoLink
+* One-way broadcasting communications: UsecaseBroadcast
+* Satellite links: UsecaseSatelliteLinks
+* Private, isolated MitM/Sybil-resistant networks: UsecaseF2F
+* Highly secure isolated air-gap computers: UsecaseAirgap
+* Network censorship bypassing, health: UsecaseCensor
+* Reconnaissance, spying, intelligence, covert agents: UsecaseSpy
+* Cheap night transfers: UsecaseCaller
+* Multicast flooding transmission: UsecaseMulticast
 @end menu
 
 @node UsecaseMail
@@ -244,6 +245,9 @@ configuration file) and send all related outbound packets and retrieve
 those the Bob has. All interrupted transfers will be automatically
 resumed.
 
+Ability to do @ref{MCD, multicast nodes discovery} of participant in
+IPv6 networks allows complete ignorance of network addresses specifying.
+
 @node UsecaseAirgap
 @section Highly secure isolated air-gap computers
 
@@ -371,21 +375,103 @@         cron: "*/1 * * * *"
         addr: lan
         nice: MAX
         onlinedeadline: 3600
-      },
+      }
       {
         cron: "*/10 * * * *"
         addr: wan
         nice: PRIORITY
         xx: rx
-      },
+      }
       {
         cron: "*/1 0-7 * * *"
         addr: wan
         nice: BULK
         onlinedeadline: 3600
         maxonlinetime: 3600
-      },
+      }
     ]
   }
 }
 @end verbatim
+
+@node UsecaseMulticast
+@section Multicast flooding transmission
+
+Do you need to send single mail message or file to many recipients at
+once? For example an update of some program, network participants list
+or available files for freqing? But you are not connected directly to
+each of them?
+
+@verbatim
+   A-------->E---->F    A -> B C E
+  / \        |\    ^    C -> H J
+ /   \       |  \  |    E -> D F G
+v     v      v    \v    D -> G
+B     C      D---->G    J -> K
+     / \     ^    /     K -> D G
+    /   \    |   /
+   v     v   v  /
+   H     J<->K<-
+@end verbatim
+
+NNCP has @ref{Multicast, multicast} packets format, allowing you to
+flood transmission of the single packet to multiple recipients.
+@strong{A} sends packet to three destinations. @strong{C} sends it to
+the two nodes next. @strong{E} sends it to three. Some participants may
+receive multiple copies of the same packet, like @strong{D}, @strong{J},
+@strong{G}, @strong{F}, but that copies will be just ignored. If
+@strong{B} sends packet to single known to him @strong{A}, then that
+packet will be distributed among all other multicast area subscribers.
+
+Moreover those multicast packets are encrypted and require key knowledge
+for reading. But that does not prevent their relaying! Also you are not
+required to know sender's public keys. That way you can easily create
+echo-conferences for files or commands (like mail message delivering)
+transmission.
+
+Let's create keys for the new multicast area:
+
+@example
+$ nncp-cfgnew -area filelists -nocomments
+areas: @{
+  filelists: @{
+    id: TOU5TKOW4JBIZJBX63D4776C72FMWDAUAUSZNJX4DFOITVYQ5ZQA
+    pub: DSHL5O6BK2R3QKJAIJ7BC4UIGE73EC2LJPOV3VTS44KYOTUQYZLA
+    prv: AYD5FAA4GDDSAD5N65NJLLFS6TG2NSPQ46KAQO5U722JLVG34SOQ
+  @}
+@}
+@end example
+
+and send that keypair everybody who wants to read that area.
+For intermediaries willing to relay packets on, but that should not read
+them, you just need to send area's identity. For example @strong{A} adds
+to his configuration:
+
+@example
+areas: @{
+  filelists: @{
+    id: TOU...
+    pub: DSH...
+    prv: AYD...
+    subs: ["B", "C", "E"]
+    incoming: /home/A/areas/filelists
+  @}
+@end example
+
+and @strong{E}, that will be relaying intermediary (as we decided):
+
+@example
+areas: @{
+  filelists: @{
+    id: TOU...
+    subs: ["D", "F", "G"]
+  @}
+@end example
+
+After you distributed the knowledge about @code{nodelist} multicast
+area, you can share @ref{FreqIndex, file lists}:
+
+@example
+$ nncp-file tree-of-A-20210715.txt.zst area:filelists:
+$ nncp-toss -node self
+@end example
diff --git a/makedist.sh b/makedist.sh
index 2c63251b857a80a5ecb88d83ed8a03175e27745eef404e12b960560d7ad16a72..a1b99f758918937b308762291dd08cbc8f96170deaf070c74765b2cd22441f65 100755
--- a/makedist.sh
+++ b/makedist.sh
@@ -104,9 +104,9 @@ perl -i -npe "s/GO test/GO test -mod=vendor/" test.do
 rm makedist.sh VERSION.do
 rm -r .git
 redo-cleanup full
-find . -type d -exec chmod 755 {} \;
-find . -type f -exec chmod 644 {} \;
-find . -type f -name "*.sh" -exec chmod +x {} \;
+find . -type d -exec chmod 755 {} +
+find . -type f -exec chmod 644 {} +
+find . -type f -name "*.sh" -exec chmod +x {} +
 chmod +x contrib/do
 
 cd ..
diff --git a/ports/nncp/Makefile b/ports/nncp/Makefile
index 9f9492ba6df4bfbe36f9fb22a4945760843d7c3baa21ebf418678d63b01fe1e9..13f72b837d22a5c14d4f740ff6d04ec6c781eb80ff4312868d4260c12990d119 100644
--- a/ports/nncp/Makefile
+++ b/ports/nncp/Makefile
@@ -1,5 +1,5 @@
 PORTNAME=	nncp
-DISTVERSION=	7.3.0
+DISTVERSION=	7.4.0
 CATEGORIES=	net
 MASTER_SITES=	http://www.nncpgo.org/download/
 
diff --git a/src/cmd/nncp-cfgnew/main.go b/src/cmd/nncp-cfgnew/main.go
index bd6ecc0bc92ea2178a1322f7809b50665403e213ea86a5bc12cb461f8f2be673..212a4d6529a74ea44d4dc6813684bbe9c0e9812fd65673ef93524eb86a7210b9 100644
--- a/src/cmd/nncp-cfgnew/main.go
+++ b/src/cmd/nncp-cfgnew/main.go
@@ -303,7 +303,7 @@     #   #     autotoss-nofile: true
     #   #     autotoss-nofreq: true
     #   #     autotoss-noexec: true
     #   #     autotoss-notrns: true
-    #   #   },
+    #   #   }
     #   # ]
     # }
   }
diff --git a/src/go.sum b/src/go.sum
index cf4b02d1f5f3422de3ade3878374f7c0940defb7be01cd5b1444e83fa1c87a54..38a2264da15ee651d60195cca17bfb138e60ed3e19c146c4ca82f6bb084b743e 100644
--- a/src/go.sum
+++ b/src/go.sum
@@ -31,11 +31,9 @@ golang.org/x/net v0.0.0-20210614182718-04defd469f4e h1:XpT3nA5TvE525Ne3hInMh6+GETgn27Zfm9dxsThnX2Q=
 golang.org/x/net v0.0.0-20210614182718-04defd469f4e/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
 golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20210423082822-04245dca01da/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1 h1:SrN+KX8Art/Sf4HNj6Zcz06G7VEz+7w9tdXTPOZ7+l4=
 golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20210616094352-59db8d763f22 h1:RqytpXGR1iVNX7psjB3ff8y7sNFinVFvkx1c8SjBkio=
 golang.org/x/sys v0.0.0-20210616094352-59db8d763f22/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1 h1:v+OssWQX+hTHEmOBgwxdZxK4zHq3yOs8F9J7mk0PY8E=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
 golang.org/x/term v0.0.0-20210615171337-6886f2dfbf5b h1:9zKuko04nR4gjZ4+DNjHqRlAJqbJETHwiNKDqTfOjfE=
 golang.org/x/term v0.0.0-20210615171337-6886f2dfbf5b/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8=
diff --git a/src/mcd.go b/src/mcd.go
index be5a0a2648f9c849de51ef10335076aa4f00b2f2a07858f31867acbdd1883244..5b64a476eb8ac30f57006858ba8d6f8d214ca0d79d4e1eaa6857807b707810d3 100644
--- a/src/mcd.go
+++ b/src/mcd.go
@@ -176,20 +176,24 @@ 	return nil
 }
 
 func (ctx *Ctx) MCDTx(ifiName string, port int, interval time.Duration) error {
-	conn, err := net.DialUDP("udp",
-		&net.UDPAddr{Port: port, Zone: ifiName},
-		&net.UDPAddr{IP: mcdIP, Port: MCDPort, Zone: ifiName},
-	)
+	ifi, err := net.InterfaceByName(ifiName)
 	if err != nil {
 		return err
 	}
+	addr := &net.UDPAddr{IP: mcdIP, Port: port, Zone: ifiName}
+	conn, err := net.ListenMulticastUDP("udp", ifi, addr)
+	if err != nil {
+		return err
+	}
+
+	dst := &net.UDPAddr{IP: mcdIP, Port: MCDPort, Zone: ifiName}
 	var buf bytes.Buffer
 	mcd := MCD{Magic: MagicNNCPDv1.B, Sender: ctx.Self.Id}
 	if _, err := xdr.Marshal(&buf, mcd); err != nil {
 		panic(err)
 	}
 	if interval == 0 {
-		_, err = conn.Write(buf.Bytes())
+		_, err = conn.WriteTo(buf.Bytes(), dst)
 		return err
 	}
 	go func() {
@@ -201,7 +205,7 @@ 					"MCD Tx %s/%d/%d",
 					ifiName, MCDPort, port,
 				)
 			})
-			_, err = conn.Write(buf.Bytes())
+			_, err = conn.WriteTo(buf.Bytes(), dst)
 			if err != nil {
 				ctx.LogE("mcd", les, err, func(les LEs) string {
 					return fmt.Sprintf("MCD on %s/%d/%d", ifiName, MCDPort, port)
diff --git a/src/nncp.go b/src/nncp.go
index e3cd31cec071c2921f035c50d652a9464133d60b8f554115027ade6d81a661e7..b0fef01cdd6dcca8df164662c0a3190d643a4cdc898814b91094ffeecb93d286 100644
--- a/src/nncp.go
+++ b/src/nncp.go
@@ -40,7 +40,7 @@
 const Base32Encoded32Len = 52
 
 var (
-	Version string = "7.3.1"
+	Version string = "7.4.0"
 
 	Base32Codec *base32.Encoding = base32.StdEncoding.WithPadding(base32.NoPadding)
 )