Protocol layers

Physical : cable
Link : MAC data
Network : IP
Transport : TCP | UDP
Session
Presentation
Application

Unbound : DNS server

Unbound files

/etc/hosts
/etc/hostname
/etc/resolv.conf : fastly write : nameserver 127.0.0.1
/etc/network/interfaces

Unbound test

route add default gw 80.81.82.22
unbound-checkconf /etc/unbound/unbound.conf

Unbound | Dns cache

systemd-resolve –flush-caches
unbound-control flush_zone google.com

Nginx : proxy

Nginx debug

sudo /etc/init.d/apache2 stop if impossible to bind to 443 or 80