orestis's questions

When I connect to a VPN network through Gnome Network-manager I lose DNS resolution and in practice, I cannot access resources inside the VPN network or outside.

When I was using Ubuntu 16.04 and I was using the VPN, the "/etc/resolv.conf/" file would contain the DNS servers of the (VPN) network I had connected. Now it always contains the following entries:

nameserver 127.0.0.53
search myprovider.com

From what I have understood 127.0.0.53 is the address of the DNS stub used by the system-resolved.

I suspect that this is a bug because the VPN was working fine the Ubuntu 16.04. Is there any way that I can set the DNS servers of my network when I am using a VPN service?

Update:

I tried connecting to the OpenVPN network with the configuration file attached at the end of the post, but I get the following error:

 Authenticate/Decrypt packet error: cipher final failed

I have verified that the server uses lzo compression and I have enabled it as well. The connection stays active but I cannot navigate to any page inside or outside the VPN.

In the configuration file listed below, I have included the solutions posted in the replies

 client
 dev tun
 proto udp
 remote openvpn.bibsys.no 1194
 remote my-server-2 1194
 resolv-retry infinite
 nobind
 user myuser
 group myuser
 persist-key
 persist-tun
 ca ca-cert.pem
 cert openvpn.crt
 key openvpn.key
 cipher AES-256-CBC
 comp-lzo yes
 script-security 2
 up /etc/openvpn/scripts/update-systemd-resolved
 down /etc/openvpn/scripts/update-systemd-resolved
 down-pre

After a new Ubuntu 18.04 installation on a empty drive, when I try to log in the computer freezes. When I log in through tty ( Ctrl+Alt+F2,F3), I can log in normally and perform tasks.

How can I debug what is happening with GNOME?

Also, when I try to shut it down, I get the error:

NMI watchdog: Watchdog detected hard LOCKUP on cpu 4

I have a Dell XPS 15 with NVMe drive.

$ uname -a
Linux kefalonia 4.15.0-20-generic #21-Ubuntu SMP Tue Apr 24 06:16:15 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

$ lshw -C cpu
  *-cpu
       description: CPU
       product: Intel(R) Core(TM) i7-7700HQ CPU @ 2.80GHz
       vendor: Intel Corp.
       physical id: 4c
       bus info: cpu@0
       version: Intel(R) Core(TM) i7-7700HQ CPU @ 2.80GHz
       serial: To Be Filled By O.E.M.
       slot: U3E1
       size: 3709MHz
       capacity: 3800MHz
       width: 64 bits
       clock: 100MHz
       capabilities: x86-64 fpu fpu_exception wp vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx pdpe1gb rdtscp constant_tsc art arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc cpuid aperfmperf tsc_known_freq pni pclmulqdq dtes64 monitor ds_cpl vmx est tm2 ssse3 sdbg fma cx16 xtpr pdcm pcid sse4_1 sse4_2 x2apic movbe popcnt aes xsave avx f16c rdrand lahf_lm abm 3dnowprefetch cpuid_fault epb invpcid_single pti tpr_shadow vnmi flexpriority ept vpid fsgsbase tsc_adjust bmi1 avx2 smep bmi2 erms invpcid mpx rdseed adx smap clflushopt intel_pt xsaveopt xsavec xgetbv1 xsaves dtherm ida arat pln pts hwp hwp_notify hwp_act_window hwp_epp cpufreq
       configuration: cores=4 enabledcores=4 threads=8

I am have a remote machine behind a firewall that I wish to connect to through SSH. As far as I understand this can be achieved by using a reverse ssh tunnel.

So the command I am using is

ssh -N -f -R 0.0.0.0:1234:localhost:22  -i /home/username/.ssh/id_rsa.pub  [email protected]

My main problem is that I want to execute this command whenever the computer starts so that the computer is accessible after a reboot.

I tried to use cron by adding the command both my user's crontab and in /etc/cron. However the problem I have is that both commands are asked for a password. I have created the id_rsa.pub file and sent it to the remote-server but still it does not seem to work.

If I am logged in (e.g. through teamviewer) I can run the command and no password is asked. If I run the command as root (sudo) the (empty) password for the rsa file is asked. I suspect that my problem is here, i.e., when cron executes the command ssh asks for the password and the command hangs.

I have tried using both my user's rsa file and the root's rsa file and with none of them I manage to connect.

I have a Dell Inspiron 15 with ATI graphics card. Everything was working without any problems until kernel 3.8. During the regular updates Ubuntu suggested to update to kernel 3.13.0.30. After that the operating system is not able to load in normal mode. Grub appears and I can login to failsafe mode with all kernels including 3.13.0.30. I can also login normally when using kernel 3.8. When using 3.13 normal login will endup to a blank screen before lightdm loads (before the login screen).

When I had installed the rar application the archive manager was using that one which had problems with non-english characters. I uninstalled it and the archive manager used p7zip. The question is how can I make the archive manage (and extract here) to use the p7zip instead of rar but have both installed at the same time.