Skip to content

How to resolve run-of-the-mill

... connection problems

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
# Check connection
ping 8.8.8.8

# Check domain resolver
ping google.com

# If pinging 8.8.8.8 works but pinging google.com doesn't, check dns file resolver
    # Add a new line: 
    # nameserver 8.8.8.8
sudo nano /etc/resolv.conf

# Check wired connections
sudo service networking

Prevent /etc/resolv.conf from updating

By default, NetworkManager dynamically updates the /etc/resolv.conf file with the DNS settings from active NetworkManager connection profiles. However, you can disable this behavior and manually configure DNS settings in /etc/resolv.conf. Steps:

1. As the root user, create the /etc/NetworkManager/conf.d/90-dns-none.conf file with the following content by using a text editor:

1
2
[main]
dns=none

2. Reload the NetworkManager service:

1
systemctl reload NetworkManager

After you reload the service, NetworkManager no longer updates the /etc/resolv.conf file. However, the last contents of the file are preserved.

3. Optionally, remove the "Generated by NetworkManager" comment from /etc/resolv.conf to avoid confusion.

Verification

1. Edit the /etc/resolv.conf file and manually update the configuration.

2. Reload the NetworkManager service:

1
2
3
4
systemctl reload NetworkManager
````   

**3.**  Display the /etc/resolv.conf file:
cat /etc/resolv.conf 
1
2
3
4
5
6
 If you successfully disabled DNS processing, NetworkManager did not override the manually configured settings.


## ...issues with screen monitors

Xrandr is used to set the size, orientation and/or reflection of the outputs for a screen. It can also set the screen size.

See commands and usage

man xrandr

List current settings

xrandr

Also, for listing current settings

xrandr --current 

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
Listing current settings helps you out to see the name of the outputs of your screens.

In my case:

```shell-session
# Place laptop to the left of DP-2 (27'')
xrandr --output eDP-1  --left-of DP-2

# Place 34'' to the right of DP-2 (27'')
xrandr --output HDMI-1 --right-of DP-2

# Rotate 27''
xrandr --output DP-2  --rotate left

... issues with monitor recognized but not displayed

Weird key sequence:

Ctrl-Alt-F3, Ctrl-Alt-F7

Last update: 2023-05-02
Created: May 2, 2023 17:36:07