Increase your Linux server Internet speed with TCP BBR congestion control

I recently read that TCP BBR has significantly increased throughput and reduced latency for connections on Google’s internal backbone networks and and YouTube Web servers throughput by 4 percent on average globally – and by more than 14 percent in some countries. The TCP BBR patch needs to be applied to the Linux kernel. The first public release of BBR was here, in September 2016. The patch is available to any one to download and install. Another option is using Google Cloud Platform (GCP). GCP by default turned on to use a cutting-edge new congestion control algorithm named TCP BBR.

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How to Install and Configure Drupal with Apache on Debian 9

Drupal is a free and open source content management system that can be used to create online content, website and user communities. It is written in PHP language, uses MySQL as a database backends and distributes under the GNU General Public License. In this article, we will demonstrate how to install Drupal 8 on Debian 9 server.

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Beginner’s Resources in Learning Debian GNU/Linux

If you’re a beginner and looking for links to help you learning Debian GNU/Linux, this list is for you. This list collects some web pages useful for knowing, installing, using, and learning Debian. This also includes where to get help, where to ask if you have any trouble. This even includes some good videos introducing Debian and the installation. Furthermore, this includes links about contributing to Debian as well.

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This is a links collection about Debian. If you need something else, we have How To Install and What To Do After Installing Debian 9.0.

Knowing Debian

Start from Wikipedia and Debian Wiki:

Reasons to use Debian

There are reasonings why use Debian:

Comparison Between Debian and Ubuntu

Here are links comparing Debian and Ubuntu.

Debian Logo

The official Debian logo is known as “Open Use Logo” containing the famous “swirl” with somewhat pink color. This logo is publicly available at official page

Command Lines

To learn how to operate command lines (or, using Terminal) in Debian, visit these good links:

Debian Releases & History

To know about Debian versions (…, 7.0 Wheezy, 8.0 Jessie, 9.0 Stretch), releases (Stable, Testing, Unstable), and its history (since 1993-2017), see Debian Wiki and Wikipedia:

Downloading Debian

Debian provides complete set of its OS and software repositories, both in binary and source code forms, for all architectures supported, via these links:

Installing Debian

To install Debian, its official wiki provides huge number of tutorials:

Debian Sources.list

Sources.list is a vital file in a Debian system which determines from where Debian must download software packages. To custom sources.list as you wish and correctly, you need to learn from these resources:

Debian Repository

How To Upgrade Debian

If you need to upgrade Debian system, upgrade all the software installed in Debian, here are links you need to learn:

Debian DFSG & Social Contract

Debian is a international free software project. It has its own policy and principles for all members to work. Here, you can learn about Debian Free Software Guidelines (DFSG) and its free software principles.

Advanced Debian

Debian is a “superman” operating system. It’s powerful, stable & configurable, also well-known to be all-purpose server system. Oh don’t forget, Debian is “the mother” of Ubuntu. You can make Debian to be a file and SMB server, to be a web server, to be VoIP Server, and to be anything you want! For those advanced purposes, you will learn from these links:

Forums for Debian

Where would you ask when you experience trouble with Debian? You can pay a paid support from anyone, and also you can ask directly Debian users and communities near you.

Paid Support



Here are some videos by community for Debian, such as for installing and reviews.

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    How To Install Debian 9 “Stretch” DVD1 with GNOME Desktop

    This tutorial guides you to install Debian 9.0 with GNOME Desktop through Graphical Installer from DVD1. You’ll first prepare 2 partitions as main and swap, then make a bootable USB and finally run the installation in step-by-step. You can follow this tutorial in either singleboot or dualboot mode. This tutorial is simplified for Ubuntu users who are never installed Debian. Happy installing!

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    a. Summary

    There are at least 9 steps to go through the Debian 9.0 Graphical Installer:

    1. Choose language
    2. Choose keyboard
    3. Configure network
    4. Setup username & password
    5. Partitioning
    6. Install base system
    7. Configure APT package manager
    8. Install desktop environment (GNOME)
    9. Install GRUB bootloader

    b. Download Debian DVD

    You just need DVD1 to install Debian. Download the DVD1 (as 3.5GB) and not the LiveDVD version one (2.2GB). Here’s Debian 9.0 Download Links.

    c. Prepare 2 Partitions

    You need to create 2 blank partitions to be the main and swap. Main partition is the place where Debian OS belongs (like C: for Windows) while swap partition is a virtual memory & hibernate storage. For main, give it at least 20GB and not less. For swap, it’s optional, you may give it 1GB. You can do this with GParted Partition Editor on Ubuntu LiveCD or such.

    For example, for this installation tutorial I created 2 partitions:

    • main partition /dev/sda6 as 42GB
    • swap partition /dev/sda3 as 2.6GB

    d. Create Bootable USB

    Don’t use Unetbootin! Use dd command instead. For example, change the ‘X‘ with your USB drive letter and ‘debian.iso‘ with your Debian image file:

    sudo dd bs=5M if=debian.iso of=/dev/sdX status=progress && sync

    If you don’t know the steps, learn it from creating a Debian-based OS bootable USB drive.

    e. Booting

    Reboot your computer to USB and you should see a Debian splash screen here. Choose “Graphical Install” from the choices.

    1. Choose Language

    First step: select a language. This will be the whole language on your desktop & applications.

    2. Configure the Keyboard

    Second step: select a keyboard layout. Default choice is safe.

    3. Configure The Network

    Third step: ignore the network interfaces shoice and press “Go Back” instead. This should bring you to the list of installation steps.

    4. Usernames & Passwords

    Fourth step: this is the most important step, determine 2 things: root password and your own account’s password. Without root password, later, you cannot configure your system and cannot install programs (worse, even you cannot install ‘sudo’).

    Root password:
    Determine a password for the root superuser of Debian.

    Nonroot Username:
    Define your own account’s username.

    Nonroot Password:
    Define your account’s password.

    This could be your real name or anything.

    5. Partitioning

    Fifth step: create main partition and swap partition.

    Choose Manual Partitioning:
    Press “Manual” and press Continue.

    Edit main partition:
    Double-click the main partition you’ve prepared and edit its properties like these:

    Edit swap partition:
    Do the similar thing to make swap partition.

    What it should look:
    See here the swap and the main partition entries. Make sure they look like that.

    Select “Finish partitioning” and continue.

    6. Install Base System

    Sixth step: after finishing the partitions and continue, the installer will install base system. Base system is the basic OS Debian should be but without GNOME desktop. You should wait for ±20 minutes (it depends on your hardware specs).

    7. Configure Package Manager

    Seventh step: after installing base system, you’ll be asked to configure APT package manager. You can go through with “Yes” or any selection here in offline mode (without network connection). Ignore any error here because you can reconfigure anything once Debian installed.

    8. Install GNOME Desktop

    Eighth step: select GNOME from the software selection. This will install GNOME Desktop as the user interface for this Debian 9.0.

    9. Install Bootloader

    Ninth step: determine GRUB Bootloader to be installed so you (if dualboot) can choose between OSes at booting time.

    Select YES:
    The installer is smart it could detect another OSes installed on the same computer. See below, it detects my Ubuntu 12.04 and 17.04, the other OSes on my laptop. So select “Yes” and Continue.

    Choose your parent disk:
    For example, if your main partition is /dev/sda6, then the parent is /dev/sda.

    Finish Installation

    Once finished, Debian asks you to reboot. Press Continue and enjoy your Debian 9.0 Stretch with GNOME desktop.

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    Debian Reveals Bug That Causes Unpredictable System Behavior In Some Intel Processors

    Debian find bugs in Intel Processors

    Users who have an Intel Skylake and Kaby Lake processors have been experiencing unpredictable system behavior that leads to data loss or corruption. This was revealed by a Debian Linux developer, Henrique de Moraes Holschuh, in a “warning” mail to Debian users.

    According to the mail, “TL;DR: unfixed Skylake and Kaby Lake processors could, in some situations, dangerously misbehave when hyper-threading is enabled.”

    This bug could be experienced in 6th and 7th generation Intel Core processors and some Intel Pentium processors. The processor/microcode bug when triggered can cause errors like system and application misbehaviors when hyper-threading is enabled.

    It should also be noted that the defect can affect any other operating system and not just Debian or Linux-based operating systems. On top of that, it is difficult to detect a potentially affected software.

    Its unpredictable nature means users of Intel processors that have been affected will need to take recommended action. To avoid it, you need to disable hyper-threading meanwhile for it to be fixed, you have to update the processor microcode.

    Is your processor Intel Skylake or Kaby Lake?

    All processor models launched before September 2015 are not Skylake or Kaby Lake processors. These older processors are not threatened by the bug. To know your processor’s model name, you can run the below command:

    grep name /proc/cpuinfo | sort -u

    With your processor model name known, you can visit the links below to know if it falls under Skylake or Kaby Lake.

    It should be noted that not all of the processors in the above lists have been affected. This is because some do not have hyper-threading support. For you to know if hyperthreading is supported, run the below command line shell:

    grep -q '^flags.*[[:space:]]ht[[:space:]]' /proc/cpuinfo &&  echo "Hyper-threading is supported"

    An alternative method is for you to check the processor’s information page from the processor lists. There, you will find information on hyper-threading. Anyhow, if your processor isn’t in the list that supports hyper-threading, then you can ignore it.

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    Suggested Read
    [Quick Tip] How To Know If You Have 32 Bit or 64 Bit Computer in Ubuntu

    What to do if your processor supports Hyperthreading

    You can wait for the updates from your Linux distribution or you can take action on your own (if you feel comfortable with it).

    • Kaby Lake Processor Models: Users who have Intel Kaby Lake processors need to disable hyper-threading in the BIOS/UEFI. You can also fix it by using the Kaby Lake microcode updates. For now, it is available only to system vendors. In this case, you can get in touch with your system vendor to find out if the BIOS/UEFI update is already available. According to the advisory, ask your system vendor to give you a BIOS/UEFI update that can fix “Intel processor errata KBL095, KBW095 or the similar one for my Kaby Lake processor”.

    It is recommended that hyper-threading should not be re-enabled until you must have installed a BIOS/UEFI update with the fix.

    • Skylake Processor Models: With Skylake processor models, users have one of two choices to make:

    1. Install the non-free “intel-microcode” package and reboot your system if your processor model in the list is 78 or 94 with 3 as the steppings of your processor. The package to install is that with base version 3.20170511.1. To know your model number and steppings, run the below command line shell:

      grep -E 'model|stepping' /proc/cpuinfo | sort -u

      If otherwise, you will need to disable hyper-threading as described in the second choice below.

    2. For processor model numbers other 78 or 94 and whose stepping is not 3, you will need to disable hyper-threading in the BIOS/UEFI configuration. You can check your motherboard manual on how to do it or contact the system vendor in other to acquire the BIOS/UEFI update that fixes “Intel erratum SKW144, SKL150, SKX150, SKZ7, or the similar one for my Skylake processor”.

    Click here to get instructions on how to install the microcode updates for Debian. For Ubuntu Linux, Canonical is already working on fixing the problem.

    The problem was first seen in January 2017 while Ocaml developers were testing a new compiler. Intel had earlier found the issue, documented and fixed it.

    Anyhow, as of now, no one has used this for a possible malware attack. We can’t rule out the possibility of someone using it for a malware attack. So users should make sure the microcode update is done or that hyper-threading should not be re-enabled until you must have installed a BIOS/UEFI update with the fix.

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    Why port 80 (HTTP) reported as open by nmap when it is closed?

    Why are some ports reported as open by nmap?
    I recently setup a small server which is running Debian 9. The purpose of this machine is to run OpenVPN server on port 443 to bypass censorship. It runs the following services and nothing else:

    1. Squid on private IP belongs to VPN pool (
    2. SSH on private IP belongs to VPN pool (
    3. DNS resolver on private IP belongs to VPN pool (
    4. OpneVPN on public IP port 443 (server_public_ip_address:443)

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    How to Install Joomla with Apache on Debian 9 (Stretch)

    Joomla is one of the most popular and widely supported open source content management system (CMS) platform in the world that can be used to build, organize, manage and publish content for websites, blogs, Intranets and mobile applications. Thie tutorial describes the installation of Joomla with Apache web server and MariaDB on Debian 9.

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    Disable Downloading DEP-11 Permanently on Ubuntu

    For newer version of Ubuntu that features Ubuntu Software, you will notice that apt-get update command downloads something called DEP-11 index files. If you prefer command line over GUI or feel that this would waste your network bandwidth, you can disable it. By following this article, your apt-get update command would never fetch DEP-11 files anymore.

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    What’s DEP-11 index files for?

    It’s a part of AppStream technology implemented on Debian GNU/Linux and family distros today so the “Software Center” program could display software info which are user-friendly and easy to install. In a simplest sense for Ubuntu users, the DEP-11 is specific index file format for Ubuntu Software. So whenever you run apt-get update command, it will always download the regular files + DEP-11 files redundantly.

    How to disable it?

    Delete the 50appstream file on /etc/apt/apt.conf.d/ directory.

    sudo rm /etc/apt/apt.conf.d/50appstream

    Or if you wish, backup it first and than delete the actual file.

    sudo mv /etc/apt/apt.conf.d/50appstream /etc/apt/50appstream_backup
    sudo rm /etc/apt/apt.conf.d/50appstream

    This will disable downloading DEP-11 permanently.

    What’s the consequence?

    The apt-get update command will no longer download any of DEP-11 index files from anywhere. This results in bandwidth saving. However, you wouldn’t be able to use Ubuntu Software properly (and this should be OK if you prefer to use command lines).


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    The Perfect Server – Debian 9 (Stretch) with Apache, BIND, Dovecot, PureFTPD and ISPConfig 3.1

    This tutorial shows how to prepare a Debian 9 server (with Apache2, BIND, Dovecot) for the installation of ISPConfig 3.1. The web hosting control panel ISPConfig 3 allows you to configure the following services through a web browser: Apache web server, Postfix mail server, Dovecot IMAP/POP3 server, MySQL, BIND nameserver, PureFTPd, SpamAssassin, ClamAV, and many more.

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