.:Modifier sudo Time-out (60 min), (à insérer en fin de fichier):.
$ sudo EDITOR=nano visudo
Defaults        timestamp_timeout=60

.:WebRTC leaks (https://ipleak.net/):.
Mozilla Firefox: Type "about:config” in the address bar. Scroll down to “media.peerconnection.enabled”, double click to set it to false.
Google Chrome: Install Google official extension WebRTC Network Limiter.

.:config/skypeforlinux:.
FATAL:setuid_sandbox_host.cc(157)] The SUID sandbox helper binary was found, but is not configured correctly. Rather than run without sandboxing I'm aborting now. You need to make sure that /usr/share/skypeforlinux/chrome-sandbox is owned by root and has mode 4755.

.:ufw - allow in all igmp traffic to 224.0.0.1 (Multicast):.
#ufw allow in to 224.0.0.1 from 192.168.1.1 proto igmp