Network Manager looks buggy

Hi mates,
I always add problems with network manager… It looks like it is buggy…
For example, sometimes I’m connected to internet, but it says that I’m offline. Sometimes I’m offline but I can’t reconnect because I get this error:

this is really strange, but it is also very annoying… Is there a way to fix this ? or at least, is there any other network manager applications that I can install ?

Many thanks

Your system is probably configured to use “wicked” for networking instead of “NetworkManager”.

Yast → Network Settings

Click on the “Global Options” tab.

Near the top of the page, there should be a section “Network Setup Method”.

You can then choose between:

Wicked Service
NetworkManage Service
Network Services Disabled

So switch it to use NetworkManager Service.

Hi nrickert, thank you for your reply.
Well, yast says that I’m already using NetworkManager :frowning:

You will need to tell us which desktop you are using (Gnome, KDE, etc)
You will also need to give more details on what you did to get that weird message.

NetworkManager is working fine for me on my laptop, though I recently switched to using “wicked” for unrelated reasons.

I using openSUSE 13.2 with KDE.
I’ve also the latest updates. I’m using WIFI (If that can help).
Well, it is very easy to reproduce this problem on both my laptop and my desktop. Just disconnect and reconnect a couple of times and then you will see that strange behaviour.

Identical problem here.

However, I don’t have to disconnect and reconnect for NetworkManager to misbehave, which has it lose all connections in a time frame somewhere between 10 minutes and about an hour. After this happens, every connection registered is unexpectedly shown as not connected, and any attempt to reconnect turns up the error message shown in the OP (except for language differences).
This requires a hard restart of NetworkManager (i. e. systemctl stop NetworkManager.service, wait a few secs, then systemctl start NetworkManager.service) and bringing up the desired connection by means of nmcli - somehow the applet doesn’t work any more, and even though I manage to bring the connection up again, the applet doesn’t display the correct state.

In order to get things unstuck a complete reboot would be necessary.

@Luca91: Do you have any virtualization scheme active? If yes, that might indicate some issues in conjunction with virtualization (although atm I don’t see how that could possibly happen). If not, this seems to be a general issue.

Besides an active virtualization scheme (libvirtd/libxl, with Xen hypervisor) I’m also using KDE.

UPDATE: Further investigating this issue revealed that NetworkManager crashes unexpectedly. Whenever the NM applet misbehaves and attempting to control NetworkManager by means of nmcli fails as well, it should be checked whether or not NetworkManager is still working (ps -ef | grep NeworkManager yields only one line of output if it has crashed), and systemctl status NetworkManager.service clearly shows that something unexpected must have happened (this is an example output of said command):

NetworkManager.service - Network Manager
   Loaded: loaded (/usr/lib/systemd/system/NetworkManager.service; enabled)
   Active: failed (Result: signal) since Di 2015-09-08 02:00:29 CEST; 18min ago
  Process: 4405 ExecStart=/usr/sbin/NetworkManager --no-daemon (code=killed, signal=ABRT)
 Main PID: 4405 (code=killed, signal=ABRT)

Sep 08 02:02:38 dhclient[4887]: DHCPDECLINE on enp3s0 to 255....)
Sep 08 02:02:38 dhclient[4887]: DHCPDISCOVER on enp3s0 to 255...)
Sep 08 02:02:38 dhclient[4887]: Received signal 15, initiatin....
Sep 08 02:02:38 NetworkManager[4405]: DHCPDECLINE on enp3s0 to...
Sep 08 02:02:38 NetworkManager[4405]: DHCPDISCOVER on enp3s0 t...
Sep 08 02:02:38 NetworkManager[4405]: Received signal 15, init...
Sep 08 02:02:38 dhclient[4887]: DHCPRELEASE on enp3s0 to 192....)
Sep 08 02:02:38 NetworkManager[4405]: DHCPRELEASE on enp3s0 to...
Sep 08 02:02:38 NetworkManager[4405]: Error: could not connect...
Sep 08 02:02:38 NetworkManager[4405]: Fatal error occured, kil...
Hint: Some lines were ellipsized, use -l to show in full.

Could you show ouput of

dmesg | tail -20

No problem, but NetworkManager needs to fail once again to get any useful messages.
The way I take it this problem seems to be linked to virtualization - when I have been tinkering with a VM NetworkManager would crash repeatedly. However, since I’m not attempting to bring up the VM since a few days NetworkManager has been stable.