Tag Archives: ubuntu

How to fix DNS problems after upgrading Ubuntu 17.10 from ubuntu 17.04/16.10/16.04


Sponsored Link



One of my friend recently upgraded his ubuntu 17.04 to ubuntu 17.10 and after the upgrade my DNS stopped working.

Use one of the solutions to fix DNS issue on Ubuntu 17.10

Solution 1

Add the google DNS server in /etc/systemd/resolved.conf file

sudo nano /etc/systemd/resolved.conf

add the following line

DNS=8.8.8.8
FallbackDNS=8.8.4.4

Save and exit the file

Restart the systemd-resolved using the following command

sudo systemctl restart systemd-resolved

Solution 2

Edit the /etc/NetworkManager/NetworkManager.conf file

sudo nano /etc/NetworkManager/NetworkManager.conf

Change

dns=dnsmasq

to

dns=systemd-resolved

restart NetworkManager using the following command

sudo systemctl restart NetworkManager

Solution 3

Edit /etc/nsswitch.conf file

sudo nano /etc/nsswitch.conf

comment out the following line

hosts: files

Save and exit the file

Solution 4

add a line nameserver 8.8.8.8 in /etc/resolv.conf

Install unbound with sudo apt-get install unbound

disable the troublesome daemon with:

sudo systemctl disable systemd-resolved

sudo systemctl stop systemd-resolved

add dns=unbound in the [main] section of

/etc/NetworkManager/NetworkManager.conf

enable unbound with:

sudo systemctl enable unbound-resolvconf

sudo systemctl enable unbound

Reboot the ubuntu PC/server

If you can share which solution worked for you is very useful for other users and if you have any other new solution that would help more users.

Note:- Some of the solutions are from askubuntu

Sponsored Link



Related posts

Multimedia Apps for the Linux Console | Linux.com


When last we met, we learned that the Linux console supports multimedia. Yes, really! You can enjoy music, movies, photos, and even read PDF files without being in an X session with MPlayer, fbi, and fbgs. And, as a bonus, you can enjoy a Matrix-style screensaver for the console, CMatrix.

You will probably have make some tweaks to your system to make this work. The examples used here are for Ubuntu Linux 16.04.

MPlayer

You’re probably familiar with the amazing and versatile MPlayer, which supports almost every video and audio format, and runs on nearly everything, including Linux, Android, Windows, Mac, Kindle, OS/2, and AmigaOS. Using MPLayer in your console will probably require some tweaking, depending on your Linux distribution. To start, try playing a video:

$ mplayer 

If it works, then hurrah, and you can invest your time in learning useful MPlayer options, such as controlling the size of the video screen. However, some Linux distributions are managing the framebuffer differently than in the olden days, and you may have to adjust some settings to make it work. This is how to make it work on recent Ubuntu releases.

First, add yourself to the video group.

Second, verify that /etc/modprobe.d/blacklist-framebuffer.conf has this line: #blacklist vesafb. It should already be commented out, and if it isn’t then comment it. All the other module lines should be un-commented, which prevents them from loading. Side note: if you want to dig more deeply into managing your framebuffer, the module for your video card may give better performance.

Add these two modules to the end of /etc/initramfs-tools/modules, vesafb and fbcon, then rebuild the initramfs image:

$ sudo nano /etc/initramfs-tools/modules
    # List of modules that you want to include in your initramfs.
    # They will be loaded at boot time in the order below.
    fbcon
    vesafb
    
$ sudo update-initramfs -u

fbcon is the Linux framebuffer console. It runs on top of the framebuffer and adds graphical features. It requires a framebuffer device, which is supplied by the vesafb module.

Now you must edit your GRUB2 configuration. In /etc/default/grub you should see a line like this:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

It may have some other options, but it should be there. Add vga=789:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash vga=789"

Reboot and enter your console (Ctrl+Alt+F1), and try playing a video. This command selects the fbdev2 video device; I haven’t learned yet how to know which one to use, but I had to use it to play the video. The default screen size is 320×240, so I scaled it to 960:

$ mplayer -vo fbdev2 -vf scale -zoom -xy 960 AlienSong_mp4.mov

And behold Figure 1. It’s grainy because I have a low-fi copy of this video, not because MPlayer is making it grainy.

MPLayer plays CDs, DVDs, network streams, and has a giant batch of playback options, which I shall leave as your homework to explore.

fbi Image Viewer

fbi, the framebuffer image viewer, comes in the fbida package on most Linuxes. It has native support for the common image file formats, and uses convert (from Image Magick), if it is installed, for other formats. Its simplest use is to view a single image file:

$ fbi filename

Use the arrow keys to scroll a large image, + and – to zoom, and r and l to rotate 90 degress right and left. Press the Escape key to close the image. You can play a slideshow by giving fbi a list of files:

$ fbi --list file-list.txt

fbi supports autozoom. With -a fbi controls the zoom factor. --autoup and --autodown tell fbi to only zoom up or down. Control the blend time between images with --blend [time], in milliseconds. Press the k and j keys to jump behind and ahead in your file list.

fbi has commands for creating file lists from images you have viewed, and for exporting your commands to a file, and a host of other cool options. Check out man fbi for complete options.

CMatrix Console Screensaver

The Matrix screensaver is still my favorite (Figure 2), second only to the bouncing cow. CMatrix runs on the console. Simply type cmatrix to start it, and Ctrl+C stops it. Run cmatrix -s to launch it in screensaver mode, which exits on any keypress. -C changes the color. Your choices are green, red, blue, yellow, white, magenta, cyan, and black.

CMatrix supports asynchronous key presses, which means you can change options while it’s running.

-B is all bold text, and -B is partially bold.

fbgs PDF Viewer

It seems that the addiction to PDF documents is pandemic and incurable, though PDFs are better than they used to be, with live hyperlinks, copy-paste, and good text search. The fbgs console PDF viewer is part of the fbida package. Options include page size, resolution, page selections, and most fbi options, with the exceptions listed in man fbgs. The main option I use is page size; you get -l, xl, and xxl to choose from:

$ fbgs -xl annoyingpdf.pdf

Learn more about Linux through the free “Introduction to Linux” course from The Linux Foundation and edX.

Disable netplan on Ubuntu 17.10


Netpaln is default network configuration tool introduced in ubuntu 17.10 and if you want to disable this to go back to old ways of configuring network use the following procedure.

Netplan is a YAML network configuration abstraction for various backends (NetworkManager, networkd).

It is a utility for easily configuring networking on a system. It can be used by writing a YAML description of the required network interfaces with what they should be configured to do. From this description it will generate the required configuration for a chosen renderer tool.

Note:- This is not recommended and this is for advanced users only

Edit the /etc/default/grub file

sudo nano /etc/default/grub

Add the following line

GRUB_CMDLINE_LINUX=”netcfg/do_not_use_netplan=true”

Save and exit the file

Now update the grub using the following command

sudo update-grub

You need to install ifupdown package

sudo apt install ifupdown

Now you can add all the interface details in /etc/network/interfaces file and reboot the ubuntu PC/server.

Sponsored Link



Related posts


Linux Foundation LFCS and LFCE: Miltos Tsatsakis | Linux.com


The Linux Foundation offers many resources for developers, users, and administrators of Linux systems. One of the most important offerings is its Linux Certification Program, which is designed to give you a way to differentiate yourself in a job market that’s hungry for your skills.

How well does the certification prepare you for the real world? To illustrate that, we will be highlighting some of those who have recently passed the certification examinations. These testimonials should help you decide if either the Linux Foundation Certified System Administrator or the Linux Foundation Certified Engineer certification is right for you.

In this article, recently LFCS and LFCE Miltos Tsatsakis answers a few questions about his certification experience.

Linux.com: How did you become interested in Linux and open source?

Miltos Tsatsakis: My magic journey with Linux and open source software started about 10 years ago, as a hobby during my MSc studies. A friend of mine suggested I should join a large wireless community in Greece. I started to play with Linux-based wireless routers like OpenWrt, using distributions like Debian and Ubuntu, as well as open source software, such as Apache, Squid, Postfix, etc. I was fascinated with the freedom that Linux has to offer and, of course, the CLI terminal. At that time, I had no idea that my hobby would become my professional career in the near future.

Linux.com: What Linux Foundation course did you achieve certification in? Why did you select that particular course?

Tsatsakis: I completed the LFCS and the LFCE certification. I already hold Red Hat RHCSA and RHCE, but I wanted to update my knowledge on newer systemd-based systems like CentOs 7.

Linux.com: What are your career goals? How do you see Linux Foundation certification helping you achieve those goals?

Tsatsakis: My goals are to dive deeper into linux internals and gain more knowledge about automation tools like Ansible. Linux Foundation certification exams are performance-based, which very much benefits my career.

Linux.com: What are your hobbies or interests? Do you participate in any open source projects at this time?

Tsatsakis: I am using Ansible a lot lately to automate various tasks for my job as a system administrator. I am also interested in monitoring tools, such as Zabbix, Prometheus, and Grafana.

Linux.com: Do you plan to take future Linux Foundation courses? If so, which ones?

Tsatsakis: For now I don’t have any plans, but in the future I am certainly willing to learn more about microservices, and especially Kubernetes (Kubernetes Fundamentals certification is an excellent choice!).

Linux.com: In what ways do you think the certification will help you as a systems administrator in today’s market?

Tsatsakis: As I said before: Exams are performance-based, which is a major benefit for my career. This type of exam shows you have sufficient, practical knowledge on Linux systems!

Linux.com: What Linux distribution do you prefer and why?

Tsatsakis: When it comes to a production environment, CentOS is my first choice. Being a Red Hat fork, it gives you the confidence of an enterprise-ready OS. As for my desktop, I always used Ubuntu.

Linux.com: Are you currently working as a Linux systems administrator? If so, what role does Linux play?

Tsatsakis: Yes. I am currently working as a Linux systems administrator (mostly CentOS based systems), dealing with various open source software, such as Apache, NGINX, haproxy, and varnish.

Linux.com: Where do you see the Linux job market growing the most in the coming years?

Tsatsakis: Linux is everywhere, but Big Data and large distributed systems is currently the hottest market.

Linux.com: What advice would you give those considering certification for their preparation?

Tsatsakis: Practice a lot! Don’t memorize commands and config files; try to understand what you are doing! Use MAN pages, read sample config files under /usr/share/doc … you will definitely use them during exams!

Linux.com: If you have found employment in the IT industry, do you feel like your certification was crucial or beneficial?

Tsatsakis: I think it was as critical and beneficial, as organizations looking for qualified staff will be more apt to trust their systems to those who have proven they have practical knowledge. Certifications are beneficial, because they allow you to improve your skills everyday. Open source is evolving very fast, so it will help you to become more skilled as a professional.

Dell Kickstarts 2018 with a Brand New Linux Laptop » Linux Magazine


Dell is one of the (or one of the only) major PC vendors that sells Linux preloaded systems. The company has announced a brand new laptop from the XPS 13 family that runs Ubuntu Linux. The 7th generation XPS 13 Developer Edition (9370) is powered by Intel’s 8th generation Quad Core processor and features a brand new chassis, new display and an even smaller bazel’s than the previous edition.

These machines are a result of Project Sputnik that was founded by Barton George, founder and lead of the project. The project started back in 2012 and celebrated it’s 5th anniversary last year.

Dell XPS 13 Developer Edition features 8th Generation Intel Quad Core, i5 (US and Canada only) and i7 versions. It comes with three different configurations for memory – 4GB, 8GB or 16GB Dual Channel SDRAM. Users can get up to 1TB of storage. It comes with a choice of UltraSharp 4K Ultra HD (3840×2160) InfinityEdge touch display or FHD (1920 x 1080) InfinityEdge display. It comes with a USB Type C port for transfer and 2 Thunderbolt 3 ports with with PowerShare, DC-In & DisplayPort. It also has a built in SD card reader.

In an exclusive interview, George told us that Dell’s engineering teams work with partners to develop drivers for supported Linux distribution. These machines comes with LTS release of Ubuntu and offer a complete out of the box experience with full support for touch screen. While Ubuntu is the officially supported OS, users can wipe the hard drive and install any OS of their choice without worrying about hardware warranty. We tested a multitude of distros on it and they worked flawlessly. Barton said they try to use the hardware components that are natively supported on Linux.

He also said that there has been a massive demand for the system and now they are making it available in some European countries including the UK, Ireland, Germany, Austria, France, Italy, Spain, Switzerland (French and German), Belgium, Netherlands, Sweden, Norway and Denmark.



Source link