user241281's questions

When I disconnect from my company's VPN in Ubuntu 21.10 (using Gnome GUI for VPN connect/disconnect), I do not have previous DNS server entries in /etc/resolv.conf. Can anybody help sorting this issue out? I will list the states below and try to explain it briefly:

After boot of Ubuntu, DNS server is correct - my local router's IP:

$ ls -al /etc/resolv.conf
lrwxrwxrwx 1 root root 34 apr 22 15:44 /etc/resolv.conf -> ../run/systemd/resolve/resolv.conf

$ cat /etc/resolv.conf | grep nameserver
nameserver 192.168.2.1

After VPN is connected, my company's DNS servers are added (note there is also 192.168.2.106 what I have no clue where comes from --> this used to be my local DNS server in the past but it does not exist anymore, so this is a first mystery for me - where this IP is taken from):

$ cat /etc/resolv.conf | grep nameserver
nameserver 21x.xx.xx.x0
nameserver 21x.xx.xx.x1
nameserver 192.168.2.106

After I disconnect the VPN - notice 2xx.xx.xx.x1 is being kept, sometimes it is even on the 1st place so it tries to use my company's DNS what is wrong:

$ cat /etc/resolv.conf | grep nameserver
nameserver 192.168.2.1
nameserver 2xx.xx.xx.x1

In journal log I found this error, not sure whether it is related:

systemd-resolved[1580]: Failed to save link data /run/systemd/resolve/netif/6: Permission denied

Any help is appreciated.

EDIT: adding some further information below. My company uses Palo Alto Global Protect VPN, I connect to it using network-manager-openconnect-gnome. I did not install any other 3rd party vpn related software. But the DNS problem I describe is present also when I connect to my personal openvpn server. My personal VPN server is configured to push 8.8.8.8 and 8.8.4.4 as DNS servers. See below, the problem is present also with this VPN.

Clean boot:

$ cat /etc/resolv.conf | grep nameserver
nameserver 192.168.2.1

Openvpn connect:

$ cat /etc/resolv.conf | grep nameserver
nameserver 8.8.8.8
nameserver 8.8.4.4

Openvpn disconnected (see one DNS from vpn was kept):

$ cat /etc/resolv.conf | grep nameserver
nameserver 192.168.2.1
nameserver 8.8.4.4

I use NFS share in my local home network. NFS mount is defined in /etc/fstab as following:

192.168.1.1:/media/Share  /media/Share     nfs     noauto,rw,hard,intr,tcp,rsize=32768,wsize=32768,users 0 0

When I suspend my laptop with NFS share mounted (mount was done via clicking on the share name in nautilus), then bring the laptop to my work place (where of course my NFS share is no longer available), resume it from suspend, enter password - it hangs there.

The only workaround I found is switch to VT3 (using ctrl+alt+f3), login there, unmount forcibly /media/Share, then switch back to VT2 and the graphical login will succeed.

Is this a bug? I used the same NFS mount on Ubuntu 17.10 and it had no issue with that.

After upgrading from Ubuntu 14.04 to 18.04 my USB modem's interface name changed from wwan0 to wwx001e101f0000. I do not mind that and also read this has some good reasons. Unfortunately vnstat stopped working for this interface:

$ vnstat -i wwx001e101f0000
Error: Unable to read database "/var/lib/vnstat/wwx001e101f0000": No such file or directory

It works properly for ethernet interface enp4s0:

$ vnstat 
Database updated: Wed Aug 29 09:09:11 2018

   enp4s0 since 08/15/2018

          rx:  24.93 GiB      tx:  10.19 GiB      total:  35.12 GiB

   monthly
                     rx      |     tx      |    total    |   avg. rate
     ------------------------+-------------+-------------+---------------
       Aug '18     24.93 GiB |   10.19 GiB |   35.12 GiB |  123.21 kbit/s
     ------------------------+-------------+-------------+---------------
     estimated     27.27 GiB |   11.15 GiB |   38.42 GiB |

   daily
                     rx      |     tx      |    total    |   avg. rate
     ------------------------+-------------+-------------+---------------
     yesterday     16.45 GiB |    2.26 GiB |   18.71 GiB |    1.86 Mbit/s
         today    107.07 MiB |  473.64 MiB |  580.71 MiB |  147.83 kbit/s
     ------------------------+-------------+-------------+---------------
     estimated       280 MiB |    1.21 GiB |    1.48 GiB |

I would need some alternative to measure consumed data as I use this modem with limited amount of data available (LTE modem). Is there any alternative? I found just a lot of tools which offers real time traffic monitoring, but I need the historical data.

I use an USB LTE modem for connecting my Ubuntu 18.04 server to LTE metwork. The modem is 12d1:1506 Huawei Technologies Co., Ltd. Modem/Networkcard. I wrote a systemd script which starts the connection at boot:

[Unit]
Description=Swan LTE connection
Requires=network-online.target
After=network-online.target

[Service]
Type=oneshot
ExecStart=/root/swan_connect.sh

[Install]
WantedBy=multi-user.target

swan_connect.sh contains:

#!/bin/bash

/bin/echo -e "AT^NDISDUP=1,1,\"internet2\"\r" > /dev/ttyUSB0
/bin/sleep 2
/usr/sbin/netplan apply

It works fine but the problem is LTE connection is dropped every 48 hours (or in case of outage) and I need to re-connect and get new IP. I do it currently by a crontab script each minute - if I can't ping an IP, then it will reconnect by these commands:

/usr/sbin/netplan apply
/bin/echo -e "AT^NDISDUP=1,0,\"internet2\"\r" > /dev/ttyUSB0
/bin/sleep 2
/bin/echo -e "AT^NDISDUP=1,1,\"internet2\"\r" > /dev/ttyUSB0
/bin/sleep 2
/usr/sbin/netplan apply

Again - it works fine but I was just thinking whether there would not be a systemd version of this re/connecting. Is it possible to make a systemd script in a way systemd would re-connect the LTE connection if dropped?

I upgraded from Ubuntu 17.10 to 18.04 and realized tap to click is not reliable anymore. Approximately 40% of taps simply does nothing. Did you notice similar issues? Is it possible to fix this? (I use lenovo l450).

Edit: I use xorg session.

I have personal webserver with ownCloud installed. This webserver has no public IP address because my internet connection does not offer it. I ordered virtual linux webserver with a public IP address and I use it just for port forwarding via SSH to allow my ownCloud server be accessible from the internet. Everything works fine and I am accessing the ownCloud via a hostname - example: "mytunneledowncloud.com".

But as I have limited high speed data on my internet connection, I would like to save some data by synchronizing ownCloud via LAN private IP address when I am at home and not via ssh tunneled public ip address of my virtual server. I am thinking whether this is even possible. I would need to resolve "mytunneledowncloud.com" as:

• private ip address - in case I am on home LAN
• public ip address - in case I am not on home LAN

To be honest, I know this is a bit "ridiculous" request, but maybe there is some "workaround" for it.

Note: I use Ubuntu on all my servers and PCs.

Important note: after entering this "question" I did some testing and realized I am able to enable the broadband connection with newer version of Ubuntu Server - 15.10. The procedure is described below. Anyway, the reason why it does not work in 14.04.04LTS is not known to me (maybe the functionality is not covered in its kernel version)

I have Huawei E3372H which I set to "modem" mode, so it does not do NAT and behaves as a modem. It works with Ubuntu 15.10 (desktop). Network manager shows possibility for creating a broadband connection and I just fill APN "internet" and that's it - after enabling this connection it works perfectly.

But how to connect my Ubuntu Server 14.04 on to the internet using this USB stick when there is no NetworkManager installed?

Here is some basic info about the stick:

lsusb shows it as:

Bus 002 Device 009: ID 12d1:1506 Huawei Technologies Co., Ltd. Modem/Networkcard

This interface is being created once the stick is connected to my Ubuntu Desktop PC:

wwx001e101f0000 Link encap:Ethernet  HWaddr 00:1e:10:1f:00:00  
          BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

I tried following this (https://johnlewis.ie/mobile-broadband-from-the-command-line-in-ubuntu/) procedure, but unfortunately I ended with no success:

Apr  9 16:32:32 test_server pppd[20296]: pppd 2.4.5 started by jim, uid 0
Apr  9 16:32:33 test_server chat[20298]: abort on (BUSY)
Apr  9 16:32:33 test_server chat[20298]: abort on (VOICE)
Apr  9 16:32:33 test_server chat[20298]: abort on (NO CARRIER)
Apr  9 16:32:33 test_server chat[20298]: abort on (NO DIALTONE)
Apr  9 16:32:33 test_server chat[20298]: abort on (NO DIAL TONE)
Apr  9 16:32:33 test_server chat[20298]: send (ATZ^M)
Apr  9 16:32:33 test_server chat[20298]: expect (OK)
Apr  9 16:32:33 test_server chat[20298]: ^M
Apr  9 16:32:33 test_server chat[20298]: OK
Apr  9 16:32:33 test_server chat[20298]:  -- got it
Apr  9 16:32:33 test_server chat[20298]: send (AT+CGDCONT=1,"IP","internet"^M)
Apr  9 16:32:34 test_server chat[20298]: expect (OK)
Apr  9 16:32:34 test_server chat[20298]: ^M
Apr  9 16:32:34 test_server chat[20298]: ^M
Apr  9 16:32:34 test_server chat[20298]: OK
Apr  9 16:32:34 test_server chat[20298]:  -- got it
Apr  9 16:32:34 test_server chat[20298]: send (ATDT*99#^M)
Apr  9 16:32:34 test_server chat[20298]: expect (CONNECT)
Apr  9 16:32:34 test_server chat[20298]: ^M
Apr  9 16:32:34 test_server chat[20298]: ^M
Apr  9 16:32:34 test_server chat[20298]: CONNECT
Apr  9 16:32:34 test_server chat[20298]:  -- got it
Apr  9 16:32:34 test_server chat[20298]: send (^M)
Apr  9 16:32:34 test_server pppd[20296]: Script /usr/sbin/chat -v -f /etc/chatscripts/pap -T *99# finished (pid 20297), status = 0x0
Apr  9 16:32:34 test_server pppd[20296]: Serial connection established.
Apr  9 16:32:34 test_server pppd[20296]: using channel 10
Apr  9 16:32:34 test_server pppd[20296]: Using interface ppp0
Apr  9 16:32:34 test_server pppd[20296]: Connect: ppp0 <--> /dev/ttyUSB0
Apr  9 16:32:35 test_server pppd[20296]: sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0xce74b2a1> <pcomp> <accomp>]
Apr  9 16:33:02 test_server pppd[20296]: message repeated 9 times: [ sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0xce74b2a1> <pcomp> <accomp>]]
Apr  9 16:33:05 test_server pppd[20296]: LCP: timeout sending Config-Requests
Apr  9 16:33:05 test_server pppd[20296]: Connection terminated.
Apr  9 16:33:06 test_server pppd[20296]: Modem hangup

Edit: I found out working procedure, but unfortunately it works just on my desktop with Ubuntu 15.10:

echo -e "AT^NDISDUP=1,1,\"internet\"\r" > /dev/ttyUSB0
dhclient -v wwx001e101f0000

--> Using the commands above will bring up working mobile broadband on wwx001e101f0000 ethernet interface.

Unfortunately on my Ubuntu Server 14.04 via command dhclient -v wwan0 an ip address is not provided although the modem is connected to the LTE network (blue light on). It is very strange.

Edit2: I found out the issue is most likely in Ubuntu 14.04 kernel version. I did a test - installed new "test" Ubuntu Server 14.04 just for this test - the behavior was exactly the same as on my "production" Ubuntu Server 14.04 - no IP acquired using dhclient wwan0.

Then I installed new "test" Ubuntu Server 15.10 and in this installation it works perfectly. So I assume from some reason this ncm interface does not work properly. I noticed this difference between the 2 servers:

Ubuntu 14.04 Dmesg:

Apr  9 19:32:13 ubuntu kernel: [27410.720039] usb 1-4: new high-speed USB device number 18 using ehci-pci
Apr  9 19:32:13 ubuntu kernel: [27410.861148] usb 1-4: New USB device found, idVendor=12d1, idProduct=1506
Apr  9 19:32:13 ubuntu kernel: [27410.861154] usb 1-4: New USB device strings: Mfr=1, Product=2, SerialNumber=0
Apr  9 19:32:13 ubuntu kernel: [27410.861159] usb 1-4: Product: HUAWEI_MOBILE
Apr  9 19:32:13 ubuntu kernel: [27410.861163] usb 1-4: Manufacturer: HUAWEI_MOBILE
Apr  9 19:32:13 ubuntu kernel: [27410.898395] option 1-4:1.0: GSM modem (1-port) converter detected
Apr  9 19:32:13 ubuntu kernel: [27410.898552] usb 1-4: GSM modem (1-port) converter now attached to ttyUSB0
Apr  9 19:32:13 ubuntu kernel: [27410.943023] huawei_cdc_ncm 1-4:1.1: MAC-Address: 00:1e:10:1f:00:00
Apr  9 19:32:13 ubuntu kernel: [27410.943029] huawei_cdc_ncm 1-4:1.1: setting rx_max = 16384
Apr  9 19:32:13 ubuntu kernel: [27410.968250] huawei_cdc_ncm 1-4:1.1: cdc-wdm0: USB WDM device
Apr  9 19:32:13 ubuntu kernel: [27410.968657] huawei_cdc_ncm 1-4:1.1 wwan0: register 'huawei_cdc_ncm' at usb-0000:00:1a.7-4, Huawei CDC 
NCM device, 00:1e:10:1f:00:00

Ubuntu 15.10 Dmesg:

Apr  9 22:29:20 ubuntu kernel: [   64.269728] usb 2-1.2: new high-speed USB device number 7 using ehci-pci
Apr  9 22:29:20 ubuntu kernel: [   64.367373] usb 2-1.2: New USB device found, idVendor=12d1, idProduct=1506
Apr  9 22:29:20 ubuntu kernel: [   64.367379] usb 2-1.2: New USB device strings: Mfr=1, Product=2, SerialNumber=0
Apr  9 22:29:20 ubuntu kernel: [   64.367382] usb 2-1.2: Product: HUAWEI_MOBILE
Apr  9 22:29:20 ubuntu kernel: [   64.367384] usb 2-1.2: Manufacturer: HUAWEI_MOBILE
Apr  9 22:29:21 ubuntu kernel: [   64.459900] usbcore: registered new interface driver usbserial
Apr  9 22:29:21 ubuntu kernel: [   64.459910] usbcore: registered new interface driver usbserial_generic
Apr  9 22:29:21 ubuntu kernel: [   64.459918] usbserial: USB Serial support registered for generic
Apr  9 22:29:21 ubuntu kernel: [   64.507601] usbcore: registered new interface driver option
Apr  9 22:29:21 ubuntu kernel: [   64.507614] usbserial: USB Serial support registered for GSM modem (1-port)
Apr  9 22:29:21 ubuntu kernel: [   64.507691] option 2-1.2:1.0: GSM modem (1-port) converter detected
Apr  9 22:29:21 ubuntu kernel: [   64.507963] usb 2-1.2: GSM modem (1-port) converter now attached to ttyUSB0
Apr  9 22:29:21 ubuntu kernel: [   64.535895] usbcore: registered new interface driver cdc_ncm
Apr  9 22:29:21 ubuntu kernel: [   64.542625] usbcore: registered new interface driver cdc_wdm
Apr  9 22:29:21 ubuntu kernel: [   64.579935] huawei_cdc_ncm 2-1.2:1.1: MAC-Address: 00:1e:10:1f:00:00
Apr  9 22:29:21 ubuntu kernel: [   64.579940] huawei_cdc_ncm 2-1.2:1.1: setting rx_max = 16384
Apr  9 22:29:21 ubuntu kernel: [   64.587318] huawei_cdc_ncm 2-1.2:1.1: NDP will be placed at end of frame for this device.
Apr  9 22:29:21 ubuntu kernel: [   64.587427] huawei_cdc_ncm 2-1.2:1.1: cdc-wdm1: USB WDM device
Apr  9 22:29:21 ubuntu kernel: [   64.587579] huawei_cdc_ncm 2-1.2:1.1 wwan0: register 'huawei_cdc_ncm' at usb-0000:00:1d.0-1.2, Huawei CDC NC
M device, 00:1e:10:1f:00:00

So in Ubuntu 15.10 there are additional "usbcore" and "usbserial" entries logged and also eth interface wwan0 is being renamed to wwx001e101f0000. I will try to upgrade kernel of my Ubuntu 14.04 to the higher version and will check whether it will work there.

Important note: When doing my tests I installed Ubuntu Server 14.04.2 iso image. This one had older 3.x kernel version. Now I downloaded 14.04.4 from Ubuntu website and after installation I can see it had kernel 4.2. Interesting is on my "production" server I have Ubuntu Server version 14.04.4, but the Kernel there is 3.16: Welcome to Ubuntu 14.04.4 LTS (GNU/Linux 3.16.0-53-generic x86_64). I update the server on regular basis, but it looks from some reason linux-generci-lts-wily is included in the downloaded 14.04.4, but is not present in my 14.04.4 which had been several times updated.

New installation of 14.04.4:

$ sudo dpkg -l linux-generic-lts-*
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name                          Version             Architecture        Description
+++-=============================-===================-===================-================================================================
ii  linux-generic-lts-wily        4.2.0.27.21         amd64               Complete Generic Linux kernel and headers

So apt-get install linux-generic-lts-wily solved the problem on my Ubuntu Server - it installed 4.2 kernel and with this one it works properly.

recently I bought new laptop which had 14" 1920x1080 screen. I would like to use multi monitor setup and I have 23" 1920x1080 screen at work and 22" 1680x1050 screen at home. I would like to use it at home and at work as well. I am playing a bit with the setting. Recently I found out the scale slider in Display setting in Ubuntu (Unity) works strange - you can set the scale factor for each display separately, but:

• you scale only menu and title bars -- who needs this? If I want to scale down or up I am interested in scale globally, otherwise I will have large menus and small application buttons, text, etc or vice versa. So what is this feature good for?
• second thing - I noticed when I upscale the display, not only menus and title bars are being scaled up, but also all fonts in the GUI is being scaled up. When downscaling, all other fonts except of the menu font, remains the same size. Is this as designed?

And the "question of the day": can I get reasonable setting to have comfortable size on both displays with different dpi?

I have an ubuntu router with Ubuntu server 14.04 installed. Physical network interfaces are:

eth0 - local LAN
eth3 - WAN (internet)
wlan2 - local wireless LAN (AP)

This is my /etc/network/interfaces:

# The loopback network interface
auto lo
iface lo inet loopback

# LAN interface
auto eth0
iface eth0 inet manual

# This is the Wireless section.
auto wlan2
iface wlan2 inet manual
 up /sbin/ifconfig wlan0 up

# This is the Bridge section.
auto br0
iface br0 inet static
address 192.168.2.106
network 192.168.2.0
netmask 255.255.255.0
bridge_ports eth0 wlan0

# WAN network interface (NAT-ed)
auto eth3
iface eth3 inet static
address 192.168.1.1
netmask 255.255.255.0
gateway 192.168.1.20
dns-nameservers 8.8.8.8 4.4.4.4

Route is:

Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
default         192.168.1.20    0.0.0.0         UG    0      0        0 eth3
192.168.1.0     *               255.255.255.0   U     0      0        0 eth3
192.168.2.0     *               255.255.255.0   U     0      0        0 br0

I use UFW and this is what I have added to /etc/ufw/before.rules:

# Configure NAT settings
*nat
:POSTROUTING ACCEPT [0:0]
-A POSTROUTING -s 192.168.2.0/24 -o eth3 -j MASQUERADE
COMMIT

UFW's status:

Status: active

To                         Action      From
--                         ------      ----
22                         ALLOW       Anywhere
80                         ALLOW       Anywhere
443                        ALLOW       Anywhere
Anywhere                   ALLOW       192.168.2.0/24
22 (v6)                    ALLOW       Anywhere (v6)
80 (v6)                    ALLOW       Anywhere (v6)
443 (v6)                   ALLOW       Anywhere (v6)

Then I use also hostapd for wifi AP. Everything works perfectly. But... What I want to do is to add an additional network card which would be second WAN interface on which I have a public static IP. I want to use current eth3 as a main internet connection as it is very fast and reliable connection, but is behind a NAT, so it lacks public IP. I have additional internet connection with a public ip which I want to use only for accessing the server(router) from outside (ssh, http, https). The public IP internet connection would be connected to the eth2.

I do not know how to configure that. When I just enter this configuration into /etc/network/interfaces, I can't access the server (ssh,http,https) via a public IP specified for eth2. (internet connection with this public ip is ok - I tested it with different HW router and I could access it well from outside):

# WAN network interface with a public IP
auto eth2
iface eth2 inet static
address 217.XXX.XXX.AAA
netmask 255.255.255.224
gateway 217.XXX.XXX.BBB
dns-nameservers 8.8.8.8 4.4.4.4

Can anybody help me sorting this out?

OK, I partially solved the issue.>>>

I created new routing table and added routing for the "public ip WAN" and added an ip rule so everything which comes from the public ip will be routed using the new routing table to the correct interface/gw:

sudo ip route add 217.XXX.XXX.160/27 dev eth2 src 217.XXX.XXX.185 table T1
sudo ip route add default via 217.XXX.XXX.161 table T1
sudo ip rule add from 217.XXX.XXX.185 table T1

Now I have the server accessible from outside via public IP associated to WAN eth2. What worries me, that since I configured this, I have no access to the server via public IP from the LAN behind the router. I think this is because of masquerading is set in a way we route everything from LAN behing the router via eth3 - which is a WAN interface eht3 (without a public IP). Am I right? Is there a way how to fix this?

my Ubuntu does not suspend sometimes. Computer suspends several times correctly (2-3x) and then suddenly suspend process hangs with blinking cursor in upper left cornet and I can only reset the computer with reset button. I noticed this behaviour since upgrading from Ubuntu 13.10 to 14.04. I tried upgrading also from 14.04 to 14.10 (upgrade, not clean install) and the issue is still present. I use nvidia vga with proprietary drivers installed by "Additional Drivers" tool in Ubuntu.

Can anybody suggest how to diagnose this issue? What log should one look in for the suspend related messages?