/etc/network/interfaces:
# The primary network interface
auto eno1
#iface eno1 inet dhcp
iface eno1 inet static
address 5.196.xx.172
netmask 255.255.255.255
gateway 5.196.xx.254
pointopoint 5.196.xx.254
# dns-* options are implemented by the resolvconf package, if installed
dns-nameservers 213.186.33.99 8.8.8.8
dns-search freeit.org
iface eno1 inet6 static
address 2001:41d0:a:yyac::1
netmask 64
up /sbin/ip -f inet6 route add 2001:41d0:a:yyff:ff:ff:ff:ff dev eno1
up /sbin/ip -f inet6 route add default gw 2001:41d0:a:yyff:ff:ff:ff:ff
down /sbin/ip -f inet6 route del default gw 2001:41d0:a:yyff:ff:ff:ff:ff
down /sbin/ip -f inet6 route del 2001:41d0:a:yyff:ff:ff:ff:ff dev eno1
# The primary network interface
auto eno1
#iface eno1 inet dhcp
iface eno1 inet static
address 5.196.xx.172
netmask 255.255.255.255
gateway 5.196.xx.254
pointopoint 5.196.xx.254
# dns-* options are implemented by the resolvconf package, if installed
dns-nameservers 213.186.33.99 8.8.8.8
dns-search freeit.org
iface eno1 inet6 static
address 2001:41d0:a:yyac::1
netmask 64
up /sbin/ip -f inet6 route add 2001:41d0:a:yyff:ff:ff:ff:ff dev eno1
up /sbin/ip -f inet6 route add default gw 2001:41d0:a:yyff:ff:ff:ff:ff
down /sbin/ip -f inet6 route del default gw 2001:41d0:a:yyff:ff:ff:ff:ff
down /sbin/ip -f inet6 route del 2001:41d0:a:yyff:ff:ff:ff:ff dev eno1
root@myserver:~# service networking restart
Job for networking.service failed because the control process exited with error code. See "systemctl status networking.service" and "journalctl -xe" for details.
root@myserver:~# systemctl status networking.service
● networking.service - Raise network interfaces
Loaded: loaded (/lib/systemd/system/networking.service; enabled; vendor preset: enabled)
Drop-In: /run/systemd/generator/networking.service.d
└─50-insserv.conf-$network.conf
Active: failed (Result: exit-code) since Sun 2016-08-14 17:44:31 CEST; 7s ago
Docs: man:interfaces(5)
Process: 6645 ExecStart=/sbin/ifup -a --read-environment (code=exited, status=1/FAILURE)
Process: 6638 ExecStartPre=/bin/sh -c [ "$CONFIGURE_INTERFACES" != "no" ] && [ -n "$(ifquery --read-environment --list --exclude=lo)" ] && udevadm settle (code=exited, status=0/SUCCESS)
Main PID: 6645 (code=exited, status=1/FAILURE)
Aug 14 17:44:31 myserver systemd[1]: Starting Raise network interfaces...
Aug 14 17:44:31 myserver ifup[6645]: RTNETLINK answers: File exists
Aug 14 17:44:31 myserver ifup[6645]: Failed to bring up eno1.
Aug 14 17:44:31 cinnamon systemd[1]: networking.service: Main process exited, code=exited, status=1/FAILURE
Aug 14 17:44:31 myserver systemd[1]: Failed to start Raise network interfaces.
Aug 14 17:44:31 myserver systemd[1]: networking.service: Unit entered failed state.
Aug 14 17:44:31 myserver systemd[1]: networking.service: Failed with result 'exit-code'.
root@myserver:~#