NetworkManager error after adding ipv6 to config?

Question

Computer networks

I have an Ubuntu 16.04 server on firstvds, I needed iPv6 from the server, bought an ip address from it, added it according to the instructions from firstvds and got the following config in sudo vim /etc/network/interfaces:

source /etc/network/interfaces.d/*

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
auto ens3
iface ens3 inet static
        address ********
        netmask *******
        network *******
        broadcast *******
        gateway *******
        # dns-* options are implemented by the resolvconf package, if installed
        dns-nameservers *******
        dns-search ru

# ipv6
auto ens6
iface ens6 inet6 static
        address 2a01:230:***:***::***
        gateway 2a01:230:***:***::***
        netmask 64

then I restarted the server and try to see the open network interfaces using the ifconfig command, but the added ens6 is not there:

ens3   Link encap:Ethernet  HWaddr 52:54:00:b1:dd:a2
          inet addr:**.***.***.**  Bcast:**.***.***.**  Mask:255.255.254.0
          inet6 addr: mr20::5052:frv:feb1:deva2/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:897549 errors:0 dropped:0 overruns:0 frame:0
          TX packets:171418 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:57873639 (57.8 MB)  TX bytes:610805340 (610.8 MB)

lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:31420 errors:0 dropped:0 overruns:0 frame:0
          TX packets:31420 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1
          RX bytes:140935688 (140.9 MB)  TX bytes:140935688 (140.9 MB)

* hidden server ip
When restarting Network Manager the following error:

sudo 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.

● 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-$network.conf
   Active: failed (Result: exit-code) since Sat 2017-01-28 17:52:46 MSK; 28s ago
     Docs: man:interfaces(5)
  Process: 1118 ExecStart=/sbin/ifup -a --read-environment (code=exited, status=1/FAILURE)
  Process: 1112 ExecStartPre=/bin/sh -c [ "$CONFIGURE_INTERFACES" != "no" ] && [ -n "$(ifquery --read-environment --list --exclude=lo)" ] && udevadm settle (code=exited, status=0/SUCCESS)
 Main PID: 1118 (code=exited, status=1/FAILURE)

journalctl -xe

Jan 28 17:52:46 ******** systemd[1]: Starting Raise network interfaces...
-- Subject: Unit networking.service has begun start-up
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit networking.service has begun starting up.
Jan 28 17:52:46 ****** ifup[1118]: Cannot find device "ens6"
Jan 28 17:52:46 ****** ifup[1118]: Failed to bring up ens6.
Jan 28 17:52:46 ****** systemd[1]: networking.service: Main process exited, code=exited, status=1/FAILURE
Jan 28 17:52:46 ****** systemd[1]: Failed to start Raise network interfaces.
-- Subject: Unit networking.service has failed
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit networking.service has failed.
--
-- The result is failed.
Jan 28 17:52:46 ****** systemd[1]: networking.service: Unit entered failed state.
Jan 28 17:52:46 ****** systemd[1]: networking.service: Failed with result 'exit-code'.
Jan 28 17:52:46 ****** sudo[1105]: pam_unix(sudo:session): session closed for user root
Jan 28 17:53:38 ****** sudo[1150]:    febox : TTY=pts/0 ; PWD=/home/febox ; USER=root ; COMMAND=/bin/journalctl -xe
Jan 28 17:53:38 ****** sudo[1150]: pam_unix(sudo:session): session opened for user root by febox(uid=0)

What could be the matter? searching for information turned up nothing

Answer 1

you need to assign an ipv6 address to the ens3 interface