Can not double boot ubuntu 18.04 with winmdows 10

I want to double boot Ubuntu next to Windows 10. I already have Windows 10 installed, but I have problems installing Ubuntu.

I have created a space for installing Linux using the Disk Manager in Windows.
I've etched the iso image on the USB drive
Quick and secure startup is disabled
When I go to the installation, I do not see the window in which you can choose the type of installation, but the only disk on which I can install Ubuntu is this USB stick with an image.

I'm using ASUS VivoBook X512FJ.

I have encountered similar problems, but none exactly like mine.
And please do not say that I have to choose "something else" to the type of installation because I do not see this window.

Upgrading from 16:10 to 18:04 [duplicate]

This question already has an answer here:

  • How to install software or upgrade an old unsupported version?

    9 answers

  • Can I ignore publications during the upgrade?

    16 Answers

I found this problem during the upgrade:
enter the description of the image here

Any help please.

Problem of sound input with Asus X551CA, Ubuntu 18.04 LTS

I'm using an Asus X551CA laptop, with Ubuntu 18.04 LTS. Now the laptop comes with only one audio jack for input and output. But every time I connect a headset to it, only the audio output comes in and the microphone is not detected. The headset is fully functional, as I have checked on other devices.

Please suggest how to solve this problem.

Ubuntu 18.04 PXE Network Boot Failure

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apt – Why do I have two versions of PostgreSQL in Ubuntu 18.04?

Whenever I install PostgreSQL in Ubuntu 18.04 (even when I ask apt-get to specifically install version 11 with a sudo apt-get install postgresq-11I'm getting version 10 and version 11 on my system.

andre @ linuxrocks: / var / lib / postgresql $ ls -la
total 48
drwxr-xr-x 5 postgres postgres 4096 Jul 18 01:17.
drwxr-xr-x 86 root root 4096 July 5 14:54 ..
drwxr-xr-x 3 postgres postgres 4096 16 June 19:19 10
drwxr-xr-x 3 postgres postgres 4096 13 July 00 00:37 11

The objects in the database are repeated in these two folders.

postgres = # ! find ~ -type f -name 16563
/ var / lib / postgresql / 11 / main / base / 13132/16563
/ var / lib / postgresql / 10 / main / base / 16385/16563

I have two of them postgresql.conf, one in each folder, although the DBMS only seems to get its configs from the folder in the folder 11.

I've detected this strange behavior after doing a ps -f -u postgres to see all PostgreSQL processes and see that my system has created duplicate processes (one in a folder on 10 and another in one on 11). So I purged and reinstalled PostgreSQL (with sudo apt-get install postgresq-11) and now I do not have duplicate processes anymore.

andre @ linuxrocks: ~ $ ps -f -u postgres
PPID UID TIME C TIME TTY CMD
postgres 1595 1 0 14:30? 00:00:00 / usr / lib / postgresql / 11 / bin / postgres -D / var / lib / postgresql / 11 / may
postgres 1684 1595 0 14:30? 00:00:00 postgres: 11 / main: recorder
postgres 1692 1595 0 14:30? 00:00:00 postgres: 11 / main: checkpointer
postgres 1693 1595 0 14:30? 00:00:00 postgres: 11 / main: background author
postgres 1694 1595 0 14:30? 00:00:00 postgres: 11 / main: copywriter
postgres 1695 1595 0 14:30? 00:00:00 postgres: 11 / main: autovacuum launcher
postgres 1696 1595 0 14:30? 00:00:00 postgres: 11 / main: collector statistics
postgres 1697 1595 0 14:30? 00:00:00 postgres: 11 / main: logical replication launcher
postgres 11074 11073 0 14:33 pts / 0 00:00:00 bash
postgres 11078 11074 0 14:33 pts / 0 00:00:00 / usr / lib / postgresql / 11 / bin / psql
postgres 11091 1595 0 14:33? 00:00:00 postgres: 11 / main: postgres postgres [local] idle

Despite everything, I have both folders and duplicate objects. Why is this happening?

Can not change the wallpaper – Xubuntu 18.04

I use Xubuntu 18.04 on my personal laptop, but I can not change the screen background. I did it before by right-clicking on the desktop and modifying desktop properties.

Right now, the right click does not work anymore (nothing happens when I open the system settings, I can see all the options but not "Desktop." Even when I open "Appearance", no tab concerns the modification of the bottom of screen.

I am wondering if I have modified or uninstalled a module related to the desktop configuration.

Clues?

Ubuntu 18.04: The docker calling cron tasks silently fails in the running parts, but works in the simple crontab

I've copied several cron tasks from a CentOS 7 server, where they were running cron.daily, on a new Ubuntu 18.04 server. Tasks call fixed menu containers and look like this:

#! / bin / bash
/ usr / bin / docker exec container name script.sh name

Scripts are executable and work properly when called by the root of a shell:

/etc/cron.daily/script.sh # it works

In addition, when I call the scripts directly from / etc / crontab they work:

35 0 * * * root /etc/cron.daily/script.sh # it works

However, they should be invoked by run-parts:

45 * * * * root cd / && run-parts --report /etc/cron.hourly
25 6 * * * Root test -x / usr / sbin / anacron || (cd / && run-parts --report /etc/cron.daily)

This fails silently both when the script is in cron.hourly and cron.daily. The syslog contains lines like:

July 17 09:45:01 CRON servername[5436]: (root) CMD (cd / && run-parts -v /etc/cron.hourly)

In other words, run-parts call. Other scripts in cron.hourly and cron.daily who do not call docker seem to work. There is no error message that I can find. On CentOS, I would have assumed that it was a problem related to SELinux, but I'm puzzled. The scripts are executable (otherwise they could not have been called since crontab), the docker client is not interactive and does not use the terminal (no -he).

What could be the problem?

Note that I have a perfect workaround here. I can just call crontab jobs, the problem is solved. I post because I want to understand why this does not work when the scripts are invoked by runtime parts so that I can avoid committing a similar error in the future.

16.04 – Stuttering / Crackling Audio in Ubuntu 18.04

The sound stutters / crackles every time you listen to external speakers / headphones or the speaker from the laptop.

I've tried several solutions to no avail, and different combinations of them:

  • https://unix.stackexchange.com/a/136591

    • Changing default sampling rate = 42100default sampling rate = 48000 at /etc/pulse/daemon.conf.

    • Changing udev-detect loading moduleudev-detect-tsched load module = 0.

      This has greatly reduced the amount of noise and slow music, but it's not perfect.

  • https://askubuntu.com/a/1067759: pulseaudio -k.

  • https://askubuntu.com/a/1135589: Add snd-hda-intel options power_save = 0 power_save_controller = N at /etc/modprobe.d/alsa-base.conf.

  • The audio stuttering of 18.04:

    • add snd-hda-intel options position_fix = 1 at /etc/modprobe.d/alsa-base.conf
    • edit for udev-detect-tsched load module = 1 in /etc/pulse/default.pa
    • add resample-method = src-sinc-best-quality in /etc/pulse/daemon.conf

    Points to other sources as well.

I have also tried:

pulseaudio -k && sudo alsa force-reload

To restart.


Other solutions that I have not tried because there is no such option for me:


I just switched from Lubuntu 16.04 to an improved version and it worked perfectly. I have a Lubuntu 18.04:

$ uname -a
Linux abcde 4.15.0-54-generic # 58-Ubuntu SMP Mon Jun 24 10:55:24 UTC 2019 x86 x64 x86_64 x86_64 GNU / Linux

18.04 – How to remove the duplicate icon on the dock?

after using

jarre xvf

Command to uncompress a file I suddenly had a second copy of the icon files on my dock, as you can see in the image below.

https://ibb.co/fFyBQvc

By clicking on the "duplicate" icon at the bottom, a new window of files opens normally, but only accessible by the "real" icon, as you can see in the help points next to the "real" icon. I do not have the option of deleting duplicate icon favorites, but I have the option "add to favorites", which is pretty odd. To give you more details, these duplicate icons do not appear on the dash if I search for "files".

Thank you in advance for any help in getting rid of this duplicate icon.

How to create a DNS server on Ubuntu 18.04




DNS or reomain NOTsoul System is the distributed database that allows you to associate zone records, such as IP addresses, with domain names. When a computer, such as your laptop or phone, needs to communicate with a remote computer, such as a web server, over the Internet, they use each other's IP addresses. People are not very good at remembering IP addresses, but they are good at remembering words and phrases in domain names. The DNS system allows users to use domain names when they interact with computers while allowing them to use IP addresses when communicating with each other.

In this guide, we'll look at how you can install and configure an authoritative DNS server for your domain names. This will allow you to have full control over your DNS information and make immediate changes to your DNS records whenever you need them.

requirements

To follow this guide, you will need:

  • An 18.04 Ubuntu server.
  • A domain name
  • A sudo user not enabled on the root server.

In order to start this guide, you must log in to your server as a non-root user.

Installation

The DNS server we will use in this guide is BIND. BIND is the most used and oldest DNS server on the Internet.

Before you install BIND, you must make sure that your server is up to date with the latest packages:

sudo apt update
sudo apt upgrade

BIND is available from the default CentOS repositories and is installed with the following command:

sudo apt install bind9 bind9utils bindDnsutils 9-doc

BIND is now installed so that we can configure it.

Global link parameters

Making BIND work as a DNS server splits into two parts. The first is to define the global parameters that will allow BIND to function as desired. The second is to create the domain-specific DNS information that BIND will serve. This information is called "zone information" or "zone record".

In this section, we will configure the global settings.

The first configuration file we are going to edit is at /etc/bind/named.conf.options and configure the operation of bind. Open this file with your favorite text editor here nano is used:

sudo nano / etc /bind/named.conf.options

edit named.conf.options so that it looks like the following:

options {
directory "/ var / cache / bind";
auth-nxdomain no;
listen on port 53 {any; };
recursion no;
};

The options used here mean as follows:

  • directory – This sets a file system path variable. It does not need to be changed.
  • auth-nxdomain no – BIND will not respond with authority to unconfigured domains on this server.
  • listen on port 53 {any; }; – This defines the port on which BIND will listen for incoming DNS requests. Port 53 is the default DNS port. the all options is used here instead of an IP address. This tells BIND to connect to all available interfaces, private and public.
  • recursion no – This option configures BIND to respond only with information about the domains for which it has configuration files. If this is set to Yes then BIND will become a recursive DNS, meaning that it will look for any request for which it receives a request similar to the Google recursive server. 8.8.8.8. This should always to be set to no when BIND is also configured to respond to requests from any IP address, as we have previously indicated for security reasons. Indeed, it can be used for DNS amplification attacks or for other harmful purposes.

The second configuration file that we will create defines the domains for which BIND is responsible and where the files containing their zone information are located. Open this file with a text editor:

sudo nano / etc /bind/named.conf.local

Edit this file so that it looks like:

zone "exmaple.com" {
master type;
file "/etc/bind/forward.example.com";
};

zone "10.100.51.198.in-addr.arpa" {
master type;
file "/etc/bind/reverse.example.com";
};

The lines in this file have the following meaning:

  • zoned – This is the domain name or IP address for which BIND will respond to requests.
  • master type – BIND will read zone information from local memory and provide authoritative information for the domain indicated on the zoned line.
  • file – The file containing the zone information.

As you can see, two sections of this file have the same syntax. The first section lists the domain (example.com) and constitutes what is called a direct DNS record. This means that it will convert domain information into IP addresses.

The second is the reverse registration or PTR of the IP address of the server. This converts in the opposite direction, that is IP addresses into domain names. the zoned The line for reverse registration seems a little strange because the IP address is reversed. The IP address for which it is the reverse record is 198.51.100.10.

Inverted records are important because many security systems, such as spam filters, will accept less mail sent from an IP address without an inverted record.

Now that the global configuration of BIND is set, we can create the zone files that will contain the forward and reverse DNS information.

Configuring the zone file

The first zone file we will create is the transfer information for the domain name. Open and create the file with a text editor:

sudo nano / etc /bind/forward.example.com

And use the following as a template:

$ TTL 1d
@ IN SOA dns1.example.com. hostmaster.example.com. (
1; serial
6h; refresh after 6 hours
1h; try again after 1 hour
1w; expires after 1 week
1d); TTL minimum of 1 day
;
;
; Server name
@ IN NS ns1.example.com.
ns1 IN A 198.51.100.10
;
;
Mail server information
exemple.com. IN MX 10 mail.example.com.
mail IN A 198.51.100.20
;
;
; Additional A records:
www IN A 198.51.100.30
site IN A 198.51.100.30
;
;
; Additional CNAME records:
IN CNAME slave www.example.com.

The first configuration block starts $ TTL 1d has only one line to modify by modifying exemple.com to your domain:

exemple.com. IN SOA dns1.example.com. hostmaster.example.com. (

This line means from left to right:

  • @ – This is replaced by the domain of the named.conf.local i.e. exemple.com.
  • IN – the type of recording, in this case, INternet records.
  • SOA – The disc is the SPie OF Acommunity record. This is the authoritative record for this area.
  • dns1.example.com. – The name server where the DNS records are.
  • hostmaster.example.com. – The email address of the name server administrator. the @ The symbol is replaced by a dot.

The rest of the lines here define values ​​such as Time To Thethat you can copy from the example because they are functional values.

Note the points at the end of the domains and host names, for example. exemple.com. This last point prevents the domain name from being added automatically. We want this to happen with, for example, the www in the next line www IN A 198.51.100.10 as that will solve www.example.com at the IP address.

The next section – Name Server Information – is mandatory and must be modified to use the host name of this name server and its IP address. It is customary to name the first name server ns1.domain.com but you can choose any host name you want.

The remaining sections are optional and are provided as an example. The first of them, Mail server information, is an example of how an email will be sent to an email server at the IP address 198.51.100.20. MX the records must always be resolved to host names, so that the required information A record for mail.exemple.com is included in the Mail Records section for ease of understanding.

The last two sections are other examples of A and CNAME recordings.

Then we have to create a reverse zone file. Open and create the file with a text editor:

sudo nano / etc /bind/reverse.example.com

Use the following example as a template:

$ TTL 1d
@ IN SOA dns1.example.com. hostmaster.example.com. (
1; serial
6h; refresh after 6 hours
1h; try again after 1 hour
1w; expires after 1 week
1d); TTL minimum of 1 day
;
;
; Server name
@ IN NS ns1.example.com.
ns1 IN A 198.51.100.10
;
;
; Reverse IP information
10.100.51.198.in-addr.arpa. IN PTR ns1.example.com.
20.100.51.198.in-addr.arpa. IN PTR mail.example.com.
30.100.51.198.in-addr.arpa. IN PTR www.example.com.

The first two sections are identical to the transfer zone file. The last section configures the IP on the domain name registrations.

The IP address listed in the previous format with the host name that you want to resolve at the end of the line. Here, reverse maps are defined for the three IP addresses used in the transfer zone file as an example.

Check your configuration for errors

BIND provides two tools to verify that its configuration files contain no errors that prevent BIND from starting.

The first checks the global configuration files and is used as follows:

sudo named-checkconf / etc /bind/named.conf.options
sudo named-checkconf / etc /bind/named.conf.local

The second tool checks the zone files and is used as follows:

sudo named-checkzone  



for example.
sudo named-checkzone example.com / etc /bind/forward.example.com

When you have finished editing these files and they do not generate any errors when you check that BIND needs to be restarted and enabled before you can start at startup:

sudo systemctl activate bind9.service
sudo systemctl restart bind9.service

Configure Systemd to keep BIND running

When you start using your own name servers for your domain, it is essential that BIND is still running. If it stops, everything that uses your domain, for example email, website, etc. will stop working. Systemd is the program that, among other services, starts and stops programs such as BIND on your server. In addition to starting and stopping, it can be configured to make sure that the program is restarted if it stops for any reason.

First, make a copy of the BIND systemd service file we are going to edit:

sudo cp / lib / systemd / system /bind9.service / etc / systemd / system /

This will ensure that changes will not be lost in future system updates. Then open the file in an editor:

sudo nano / etc / systemd / system /bind9.service

And add the following two lines to the [Service] section:

Restart = always
RestartSec = 3

Then invite Systemd to reload all of its service files:

sudo systemctl daemon-reload

And restart BIND:

sudo systemctl restart bind9.service

Now, if BIND stops working for any reason, systemd will restart it automatically.

DNS server test

Before you start using your new DNS server, you must check that it is working properly, that is, BIND provides the correct DNS information for your domain.

The DNS inspection tool dig was included in the packages we installed at the beginning of this guide. dig is one of the powerful and flexible DNS command and test command line tools available in Linux and should be your goto tool for searching DNS records.

dig can ignore resolvers configured by the system (defined in /etc/resolv.conf) and request DNS information directly from a name server, which is the DNS server you just created.

The syntax of a dig the request is as follows:

dig @ -t  

If we replace this information with the example server details in this guide, we get:

dig @198.51.100.10 -t A www.example.com.

This will return a lot of information. The result that interests us is always contained in the RESPONSE SECTION for example.:

;; SECTION RESPONSE:
exemple.com. 86400 IN A 198.51.100.30

We can also check the reverse map record using the -X flag:

dig @ 198.51.100.10 -x 198.51.100.10

What will produce the result:

;; SECTION RESPONSE:
10.100.51.198.in-addr.arpa. IN PTR ns1.example.com.

You can perform similar queries on all zone records that you have created for your domain. When they return all the correct information, you are ready to use your DNS server.

Conclusion

You have now installed, configured, and successfully tested your own DNS server. You are now ready to use it. To do this, you will need to transfer your domain to your DNS server. This is done with the company that registered your domain for you. When you sign in to their site, you'll find somewhere in their control panel an option to move the domain to new, authoritative name servers.

Some companies require that a domain has more than one authoritative name server. In this guide, we have only created one, that is, ns1.example.com. If an additional name server is required, you must obtain a second virtual machine and copy the configuration by replacing ns2 for ns1.

You can also request a second IP address for your existing server and duplicate the ns1 records by changing them into ns2.