Начиная с LINUX KSI имени Кубушина с такого зверя как CyberZOO)
pacman -Syu --overwrite /usr/lib\*/p11-kit-trust.so нормально. Однако. Впервые встречаю в *nix-ax чтобы стандартное обновление вручную править надо было
sudo pacman -Syy
[sudo] password for pol:
:: Synchronizing package databases...
 core                                                135.0 KiB   332 KiB/s 00:00 [##############################################] 100%
 extra                                              1648.8 KiB   462 KiB/s 00:04 [##############################################] 100%
 community                                             4.9 MiB   460 KiB/s 00:11 [##############################################] 100%
[[email protected] ~]$ sudo pacman -Syu
:: Synchronizing package databases...
 core is up to date
 extra is up to date
 community is up to date
:: Starting full system upgrade...
resolving dependencies...
looking for conflicting packages...
warning: dependency cycle detected:
warning: systemd will be installed before its ca-certificates-mozilla dependency

Packages (56) adwaita-icon-theme-3.36.1-1  ca-certificates-mozilla-3.51.1-1  chromium-81.0.4044.113-1  flashplugin-32.0.0.363-1
              git-2.26.2-1  glib-networking-2.64.2-1  glib2-2.64.2-1  gobject-introspection-runtime-1.64.1-2
              gtk-update-icon-cache-1:3.24.18-1  gtk3-1:3.24.18-1  guile-2.2.6-2  harfbuzz-2.6.5-1  harfbuzz-icu-2.6.5-1
              iana-etc-20200401-1  imagemagick-7.0.10.7-1  intel-media-sdk-20.1.0-1  jack-0.125.0-9  libffi-3.3-3  libinput-1.15.5-1
              libmfx-20.1.0-1  libp11-kit-0.23.20-4  librsvg-2:2.48.3-1  libsecret-0.20.3-1  libtar-1.2.20-5  libtirpc-1.2.6-1
              libutil-linux-2.35.1-2  libva-2.7.1-1  libxnvctrl-440.82-1  libyaml-0.2.4-1  linux-5.6.5.arch3-1  llvm-libs-10.0.0-1
              make-4.3-3  mesa-20.0.4-2  nss-3.51.1-1  openssl-1.1.1.g-1  p11-kit-0.23.20-4  pacman-mirrorlist-20200411-1
              pepper-flash-32.0.0.363-1  pygobject-devel-3.36.0-2  python-3.8.2-2  python-gobject-3.36.0-2  python2-2.7.17-3
              systemd-245.5-1  systemd-libs-245.5-1  systemd-sysvcompat-245.5-1  util-linux-2.35.1-2  wayland-1.18.0-2
              webkit2gtk-2.28.1-1  x264-3:0.159.r2999.296494a-1  xf86-video-intel-1:2.99.917+904+gf2853658-1
              xfce4-pulseaudio-plugin-0.4.3-1  xfce4-session-4.14.2-2  xfce4-settings-4.14.3-1  xfce4-taskmanager-1.2.3-1
              xfsprogs-5.6.0-1  xfwm4-4.14.1-1

Total Installed Size:  1054.18 MiB
Net Upgrade Size:         8.13 MiB

:: Proceed with installation? [Y/n] y
(56/56) checking keys in keyring                                                 [##############################################] 100%
(56/56) checking package integrity                                               [##############################################] 100%
(56/56) loading package files                                                    [##############################################] 100%
(56/56) checking for file conflicts                                              [##############################################] 100%
error: failed to commit transaction (conflicting files)
nss: /usr/lib/p11-kit-trust.so exists in filesystem
Errors occurred, no packages were upgraded.
sudo pacman -Syu
[sudo] password for pol:
:: Synchronizing package databases...
 core                  135.0 KiB   337 KiB/s 00:00 [######################] 100%
 extra                1648.8 KiB   461 KiB/s 00:04 [######################] 100%
 community               4.9 MiB   458 KiB/s 00:11 [######################] 100%
:: Starting full system upgrade...
resolving dependencies...
looking for conflicting packages...
warning: dependency cycle detected:
warning: systemd will be installed before its ca-certificates-mozilla dependency

Packages (56) adwaita-icon-theme-3.36.1-1  ca-certificates-mozilla-3.51.1-1
              chromium-81.0.4044.113-1  flashplugin-32.0.0.363-1  git-2.26.2-1
              glib-networking-2.64.2-1  glib2-2.64.2-1
              gobject-introspection-runtime-1.64.1-2
              gtk-update-icon-cache-1:3.24.18-1  gtk3-1:3.24.18-1
              guile-2.2.6-2  harfbuzz-2.6.5-1  harfbuzz-icu-2.6.5-1
              iana-etc-20200401-1  imagemagick-7.0.10.7-1
              intel-media-sdk-20.1.0-1  jack-0.125.0-9  libffi-3.3-3
              libinput-1.15.5-1  libmfx-20.1.0-1  libp11-kit-0.23.20-4
              librsvg-2:2.48.3-1  libsecret-0.20.3-1  libtar-1.2.20-5
              libtirpc-1.2.6-1  libutil-linux-2.35.1-2  libva-2.7.1-1
              libxnvctrl-440.82-1  libyaml-0.2.4-1  linux-5.6.5.arch3-1
              llvm-libs-10.0.0-1  make-4.3-3  mesa-20.0.4-2  nss-3.51.1-1
              openssl-1.1.1.g-1  p11-kit-0.23.20-4
              pacman-mirrorlist-20200411-1  pepper-flash-32.0.0.363-1
              pygobject-devel-3.36.0-2  python-3.8.2-2  python-gobject-3.36.0-2
              python2-2.7.17-3  systemd-245.5-1  systemd-libs-245.5-1
              systemd-sysvcompat-245.5-1  util-linux-2.35.1-2  wayland-1.18.0-2
              webkit2gtk-2.28.1-1  x264-3:0.159.r2999.296494a-1
              xf86-video-intel-1:2.99.917+904+gf2853658-1
              xfce4-pulseaudio-plugin-0.4.3-1  xfce4-session-4.14.2-2
              xfce4-settings-4.14.3-1  xfce4-taskmanager-1.2.3-1
              xfsprogs-5.6.0-1  xfwm4-4.14.1-1

Total Download Size:    198.39 MiB
Total Installed Size:  1054.18 MiB
Net Upgrade Size:         8.13 MiB

:: Proceed with installation? [Y/n] Y
error: failed retrieving file 'xf86-video-intel-1:2.99.917+904+gf2853658-1-x86_64.pkg.tar.zst' from mirrors.myaegean.gr : The requested URL returned error: 403
 xf86-video-intel...   737.2 KiB   309 KiB/s 00:02 [######################] 100%
 xfce4-session-4....   318.7 KiB   464 KiB/s 00:01 [######################] 100%
(56/56) checking keys in keyring                   [######################] 100%
(56/56) checking package integrity                 [######################] 100%
(56/56) loading package files                      [######################] 100%
(56/56) checking for file conflicts                [######################] 100%
error: failed to commit transaction (conflicting files)
nss: /usr/lib/p11-kit-trust.so exists in filesystem
Errors occurred, no packages were upgraded.
Что делать?

В то время как
ping 10.44.1.1
PING 10.44.1.1 (10.44.1.1) 56(84) bytes of data.
64 bytes from 10.44.1.1: icmp_seq=1 ttl=64 time=0.141 ms
64 bytes from 10.44.1.1: icmp_seq=2 ttl=64 time=0.131 ms
1 ms это ещё по божески а то вообще давал 2 ms. Я только репу почесал и понял что лучше nmap пользоваться. Или у него такая шкала что меньше 1 ms он не воспринимает
Решено. Надо запускать nmap -Pn из под рута тогда работает
C компьютера локальной сети на arch
nmap -Pn 10.44.1.1/24
Starting Nmap 7.80 ( https://nmap.org ) at 2020-04-15 08:47 EEST
RTTVAR has grown to over 2.3 seconds, decreasing to 2.0
RTTVAR has grown to over 2.3 seconds, decreasing to 2.0
RTTVAR has grown to over 2.3 seconds, decreasing to 2.0
RTTVAR has grown to over 2.3 seconds, decreasing to 2.0
RTTVAR has grown to over 2.3 seconds, decreasing to 2.0
RTTVAR has grown to over 2.3 seconds, decreasing to 2.0
RTTVAR has grown to over 2.3 seconds, decreasing to 2.0
RTTVAR has grown to over 2.3 seconds, decreasing to 2.0
RTTVAR has grown to over 2.3 seconds, decreasing to 2.0
RTTVAR has grown to over 2.3 seconds, decreasing to 2.0
RTTVAR has grown to over 2.3 seconds, decreasing to 2.0
RTTVAR has grown to over 2.3 seconds, decreasing to 2.0
RTTVAR has grown to over 2.3 seconds, decreasing to 2.0
RTTVAR has grown to over 2.3 seconds, decreasing to 2.0
RTTVAR has grown to over 2.3 seconds, decreasing to 2.0
А с сервера (на FreeBSD) работает
is running FreeBSD at the time) to quickly find files based on name only.
$ nmap -Pn 10.44.1.1/24
Starting Nmap 7.80 ( https://nmap.org ) at 2020-04-15 08:58 EEST
Nmap scan report for 10.44.1.0
Host is up (0.0000070s latency).
All 1000 scanned ports on 10.44.1.0 are filtered

Nmap scan report for 10.44.1.1
Host is up (0.00010s latency).
Not shown: 999 closed ports
PORT   STATE SERVICE
53/tcp open  domain

Nmap scan report for 10.44.1.2
Host is up (0.0000060s latency).
All 1000 scanned ports on 10.44.1.2 are filtered

Nmap scan report for 10.44.1.3
Host is up (0.0000060s latency).
All 1000 scanned ports on 10.44.1.3 are filtered

Nmap scan report for 10.44.1.4
Host is up (0.0000070s latency).
All 1000 scanned ports on 10.44.1.4 are filtered

Nmap scan report for 10.44.1.5
Host is up (0.0000070s latency).
All 1000 scanned ports on 10.44.1.5 are filtered

Nmap scan report for 10.44.1.6
Host is up.
All 1000 scanned ports on 10.44.1.6 are filtered

А без параметров nmap на arch работает
[[email protected] ~]$ nmap  10.44.1.1/24
Starting Nmap 7.80 ( https://nmap.org ) at 2020-04-15 09:05 EEST
Nmap scan report for 10.44.1.1
Host is up (0.00081s latency).
Not shown: 999 closed ports
PORT   STATE SERVICE
53/tcp open  domain

Nmap scan report for 10.44.1.8
Host is up (0.0011s latency).
Not shown: 988 closed ports
PORT     STATE SERVICE
80/tcp   open  http
135/tcp  open  msrpc
139/tcp  open  netbios-ssn
443/tcp  open  https
445/tcp  open  microsoft-ds
3306/tcp open  mysql
3389/tcp open  ms-wbt-server
5357/tcp open  wsdapi
8009/tcp open  ajp13
8010/tcp open  xmpp
8080/tcp open  http-proxy
8081/tcp open  blackice-icecap

Nmap scan report for 10.44.1.239
Host is up (0.0031s latency).
Not shown: 999 closed ports
PORT   STATE SERVICE
80/tcp open  http

Nmap done: 256 IP addresses (3 hosts up) scanned in 8.92 seconds
Теперь понесло
TCP segment of a reassembled PDU
На это дается такой ответ из которого мало что понятно https://www.pico.net/kb/how-does-wireshark-annotate-some-packets-with-tcp-segment-of-a-reassembled-pdu
У меня на хосте MTU 1500 вроде нормально
ip link
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: enp1s10: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP mode DEFAULT group default qlen 1000
    link/ether 00:07:e9:19:6a:bb brd ff:ff:ff:ff:ff:ff
А на сервере MTU 1500 уже не работает

ping -D -g 1500 -G 9000 -h 100 10.44.5.55
PING 10.44.5.55 (10.44.5.55): (1500 ... 9000) data bytes
ping: sendto: Message too long
ping: sendto: Message too long
ping: sendto: Message too long

sudo ping -D -g 1000 -G 1500 -h 100 10.44.5.55
Password:
PING 10.44.5.55 (10.44.5.55): (1000 ... 1500) data bytes
1008 bytes from 10.44.5.55: icmp_seq=0 ttl=64 time=0.321 ms
1108 bytes from 10.44.5.55: icmp_seq=1 ttl=64 time=1.034 ms
1208 bytes from 10.44.5.55: icmp_seq=2 ttl=64 time=0.352 ms
1308 bytes from 10.44.5.55: icmp_seq=3 ttl=64 time=0.371 ms
1408 bytes from 10.44.5.55: icmp_seq=4 ttl=64 time=1.058 ms
ping: sendto: Message too long

--- 10.44.5.55 ping statistics ---
6 packets transmitted, 5 packets received, 16.7% packet loss
А 1400 нормально
sudo ping -D -g 1000 -G 1400 -h 100 10.44.5.55
PING 10.44.5.55 (10.44.5.55): (1000 ... 1400) data bytes
1008 bytes from 10.44.5.55: icmp_seq=0 ttl=64 time=0.316 ms
1108 bytes from 10.44.5.55: icmp_seq=1 ttl=64 time=1.014 ms
1208 bytes from 10.44.5.55: icmp_seq=2 ttl=64 time=0.374 ms
1308 bytes from 10.44.5.55: icmp_seq=3 ttl=64 time=0.373 ms
1408 bytes from 10.44.5.55: icmp_seq=4 ttl=64 time=0.388 ms

--- 10.44.5.55 ping statistics ---
5 packets transmitted, 5 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 0.316/0.493/1.014/0.262 ms
Вроде нашел ответ но не уверен. "По описанию очень похоже на т.н. проблему «black screen» в терминальной сессии, которая вызвана наличием на пути пакета канала с меньшим MTU . Т.е. не проходят крупные пакеты. Лечится уменьшением MTU на терминальном сервере."