[xubuntu-users] Difference: Xubuntu install vs xubuntu package

[Stuart McGraw]

Hello,

I have installed two machines that I think should be substantially
the same.  One was created be installing Ubuntu-17.04-server and
adding the xubuntu-desktop package.  The other was created by 
installing the Xubuntu-17.04-desktop release.  There is one small 
difference between them (I've noticed so far) that I would like 
to fix.

In the Xubuntu-17.04-desktop install, the applet run by Settings -> 
Network Connections lists my ethernet connection as expected.

In the Ubuntu-server+xubuntu install, Network Connections
is empty (and the little network thingie in the Indicators area
says "Ethernet device not managed".)  However there is a working 
network connection, it just seems as if Network Manager (or 
whatever it is that Network Connections applet uses) doesn't 
know about it.

My question is what could cause this difference and how do I
get the Ubuntu+xubuntu network connections applet recognize the
existing network connection, same as the Xubuntu-desktop system?
I think this has something to do with NetworkManager and/or 
systemd, both of which I am woefully ignorant about.

Some additional info -- apologies for volume of information :-(...

I have compared the packages installed on both systems.  The 
Ubuntu+xubuntu system has nearly all the packages that the 
Xubuntu-desktop system has, and the few that it is missing don't 
seem to be likely to be related to this problem.)

When installing both machines, the networks were sussed out by
the installer, I didnt give it any special instructions regarding
the network.  But the /etc/network/interfaces files were different 
on both machines.

(ubtest is the Ubuntu+xubuntu machine who's network applet doesn't 
recognize the network, and xbtest is the Xubuntu-desktop machine 
that does):

ubtest's /etc/networks/interfaces:
  auto lo
  iface lo inet loopback
  # The primary network interface
  auto enp0s3
  iface enp0s3 inet dhcp

xbtest's /etc/networks/interfaces:
  auto lo
  iface lo inet loopback

I also compared boot-time logs for both systems.  I replaced 
ubtest's interfaces file (that explicitly mentions enp0s3) with
the one from xbtest (that doesn't).  The former resulted in a 
functional network (albeit with the network applet problem); the 
latter one doesn't (as seen in the excerpted log file messages 
below) but does show where the boot-time actions of each system 
diverge which I think is the significant thing.  

Messages up to the point shown below are substantially the same 
in both machines.  But then as can be seen, the Xubuntu-desktop 
system (without the problem) does a bunch of stuff starting with 
"keyfile: add connection..." that the Ubuntu+xunbuntu system 
doesn't.  Why?

ubtest: 
Oct 04 23:25:33 ubtest NetworkManager[728]: <info>  [1507181133.4098] manager: (lo): new Generic device (/org/freedesktop/NetworkManager/Devices/0)
Oct 04 23:25:33 ubtest NetworkManager[728]: <info>  [1507181133.4413] manager: (enp0s3): new Ethernet device (/org/freedesktop/NetworkManager/Devices/1)
Oct 04 23:25:33 ubtest NetworkManager[728]: <info>  [1507181133.4534] manager: startup complete
Oct 04 23:25:33 ubtest NetworkManager[728]: <info>  [1507181133.4850] urfkill disappeared from the bus
Oct 04 23:25:33 ubtest NetworkManager[728]: <info>  [1507181133.4887] ModemManager available in the bus
Oct 04 23:25:33 ubtest systemd[1]: Started Network Manager Wait Online.
Oct 04 23:25:34 ubtest systemd[1]: Started Raise network interfaces.
Oct 04 23:25:34 ubtest systemd[1]: Reached target Network.
[ifconfig shows enp0s3 is not running, has no ipv4 address which is a
result of the replaced interfaces file I presume.]

xbtest:
Oct 04 18:46:17 xbtest NetworkManager[631]: <info>  [1507164377.0028] manager: (lo): new Generic device (/org/freedesktop/NetworkManager/Devices/0)
Oct 04 18:46:17 xbtest NetworkManager[631]: <info>  [1507164377.0070] manager: (enp0s3): new Ethernet device (/org/freedesktop/NetworkManager/Devices/1)
Oct 04 18:46:17 xbtest NetworkManager[631]: <info>  [1507164377.0089] keyfile: add connection in-memory (2d1398a2-a84c-3a86-97da-6c8094291c60,"Wired connection 1")
Oct 04 18:46:17 xbtest NetworkManager[631]: <info>  [1507164377.0129] settings: (enp0s3): created default wired connection 'Wired connection 1'
Oct 04 18:46:17 xbtest NetworkManager[631]: <info>  [1507164377.0146] device (enp0s3): state change: unmanaged -> unavailable (reason 'managed') [10 20 2]
Oct 04 18:46:17 xbtest NetworkManager[631]: <info>  [1507164377.0401] device (enp0s3): link connected
Oct 04 18:46:17 xbtest NetworkManager[631]: <info>  [1507164377.0618] urfkill disappeared from the bus
Oct 04 18:46:17 xbtest NetworkManager[631]: <info>  [1507164377.0644] ModemManager available in the bus
Oct 04 18:46:17 xbtest NetworkManager[631]: <info>  [1507164377.0876] device (enp0s3): state change: unavailable -> disconnected (reason 'none') [20 30 0]
Oct 04 18:46:17 xbtest NetworkManager[631]: <info>  [1507164377.1045] policy: auto-activating connection 'Wired connection 1'
Oct 04 18:46:17 xbtest NetworkManager[631]: <info>  [1507164377.1119] device (enp0s3): Activation: starting connection 'Wired connection 1' (2d1398a2-a84c-3a86-97da-6c8094291c60)
Oct 04 18:46:17 xbtest NetworkManager[631]: <info>  [1507164377.1132] device (enp0s3): state change: disconnected -> prepare (reason 'none') [30 40 0]
Oct 04 18:46:17 xbtest NetworkManager[631]: <info>  [1507164377.1142] manager: NetworkManager state is now CONNECTING
Oct 04 18:46:17 xbtest NetworkManager[631]: <info>  [1507164377.1216] device (enp0s3): state change: prepare -> config (reason 'none') [40 50 0]
Oct 04 18:46:17 xbtest NetworkManager[631]: <info>  [1507164377.1251] device (enp0s3): state change: config -> ip-config (reason 'none') [50 70 0]
[... continues on setting up enp0s3...]
Oct 04 18:46:18 xbtest systemd[1]: Started Raise network interfaces.
Oct 04 18:46:18 xbtest systemd[1]: Reached target Network.