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Feb 06 2020

Varnish Backend fetch failed Too many headers

Filed under Fixes, Linux

This article describes particular case of Varnish error Backend fetch failed Too many headers. This error happens when there are too many headers being sent to backend server. Here is how you can troubleshoot and fix this error. Continue reading

Feb 02 2020

FlexiSip installation and configuration on Debian 9

Filed under Linux, VoIP

Flexisip is a complete, modular and scalable SIP server suite written in C++11, comprising proxy, presence and group chat functions.

Flexisip offers an easy-to-install SIP server solution, offering all the features required to deploy your own SIP service tuned for mobile or desktop applications, “out of the box”.

Flexisip can be integrated into your SIP infrastructure for various purposes : Continue reading

Debian, Flexisip, MariaDB, Redis, VoIP
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Feb 02 2020

Flexisip error Failed to find shared library for backend mysql

Filed under Fixes, Linux, VoIP

I installed Flexisip using official documentation , installed additional components like MariaDB (MySQL) and Redis, performed initial setup of configuration files, created database and DB user.

I started flexisip services with

systemctl start flexisip-proxy flexisip-presence flexisip-conference

1	systemctl start flexisip-proxy flexisip-presence flexisip-conference

and by looking in /var/opt/belledonne-communications/log/flexisip/flexisip-conference.log I noticed the following error:

2020-02-02 03:12:30:790 liblinphone-message-Linphone core [0x56197d8a7d60] notified [global_state_changed]
2020-02-02 03:12:30:790 liblinphone-message-No charset defined forcing utf8 4 bytes specially for conference subjet storage
2020-02-02 03:12:30:790 liblinphone-message-Opening linphone database db=xxx user=xxx password='xxx' host=127.0.0.1 charset=utf8mb4 with backend Mysql
2020-02-02 03:12:30:791 liblinphone-warning-Unable to build db session with uri: Failed to find shared library for backend mysql
2020-02-02 03:12:30:791 liblinphone-error-Unable to open linphone database with uri db=xxx user=xxx password='xxx!' host=127.0.0.1 charset=utf8mb4 and backend Mysql
2020-02-02 03:12:30:791 bctbx-error-Linphone Core couldn't start because the connection to the database has failed

2020-02-02 03:12:30:790 liblinphone-message-Linphone core [0x56197d8a7d60] notified [global_state_changed]

2020-02-02 03:12:30:790 liblinphone-message-No charset defined forcing utf8 4 bytes specially for conference subjet storage

2020-02-02 03:12:30:790 liblinphone-message-Opening linphone database db=xxx user=xxx password='xxx' host=127.0.0.1 charset=utf8mb4 with backend Mysql

2020-02-02 03:12:30:791 liblinphone-warning-Unable to build db session with uri: Failed to find shared library for backend mysql

2020-02-02 03:12:30:791 liblinphone-error-Unable to open linphone database with uri db=xxx user=xxx password='xxx!' host=127.0.0.1 charset=utf8mb4 and backend Mysql

2020-02-02 03:12:30:791 bctbx-error-Linphone Core couldn't start because the connection to the database has failed

error, fix, Flexisip, MariaDB, mysql, Redis
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Jan 24 2020

Magento server performance configuration

Filed under Linux, Simple about IT

There are best practices in Magento 2 performance configuration of operating system, MySQL, PHP and webserver. This article covers important configurations of all components that will speed up the Magento site.

apache, Magento, nginx, performance, PHP, php-fpm
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Jan 24 2020

DDoS Protection With IPtables

Filed under Linux, Simple about IT

There are different ways of building your own anti-DDoS rules for iptables. This guide will describe comprehensive approach to protect server from DDoS attacks:

Select the best iptables table and chain to stop DDoS attacks
Tweak your kernel settings to mitigate the effects of DDoS attacks
Use iptables to block most TCP-based DDoS attacks
Use iptables SYNPROXY to block SYN floods

Here we’ll only cover protection from TCP-based attacks. Most UDP-based attacks are amplified reflection attacks that will exhaust the network interface card of any common server. Continue reading

attack, DDoS, iptables, kernel, prerouting, protection, sysctl
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Jan 10 2020

Selenium error: Chrome failed to start: exited abnormally

Filed under Fixes, Linux

When I launched Selenium tests In Jenkins with Maven on CentOS 7 I got:

unknown error: Chrome failed to start: exited abnormally
(unknown error: DevToolsActivePort file doesn’t exist)
(The process started from chrome location /usr/bin/google-chrome is no longer running, so ChromeDriver is assuming that Chrome has crashed.)

Full error:
org.openqa.selenium.WebDriverException: unknown error: Chrome failed to start: exited abnormally (unknown error: DevToolsActivePort file doesn't exist) (The process started from chrome location /usr/bin/google-chrome is no longer running, so ChromeDriver is assuming that Chrome has crashed.) Build info: version: '3.141.59', revision: 'e82be7d358', time: '2018-11-14T08:17:03' System info: host: 'testenv', ip: '192.168.3.33', os.name: 'Linux', os.arch: 'amd64', os.version: '3.10.0-693.17.1.el7.x86_64', java.version: '1.8.0_152' Driver info: driver.version: ChromeDriver remote stacktrace: #0 0x561bcf9f2479
Continue reading

CentOS 7, Chrome, driver, google, headless, Jenkins, Maven, Selenium
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Jan 06 2020

Ergo B501 flashing and malware cleaning

Filed under Fixes, Simple about IT

In addition to its good performance and capacitive battery, at an attractive price, the Ergo B501 firmware has several apk built-in that force the advertisement to load after some time using the device. The latest official firmware at the moment: Ergo B501_OS3.0 Lite_20171117 .

You can get rid of viruses in Ergo B501 by flashing a virus-free firmware. Continue reading

Ergo B501, firmware, flash, malware, SPFlash tool
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Jan 03 2020

Disk Encryption on CentOS using LUKS Cryptsetup

Filed under Linux

LUKS (Linux Unified Key Setup) is the standard for Linux hard disk encryption. By providing a standard on-disk-format, it does not only facilitate compatibility among distributions, but also provides secure management of multiple user passwords. In contrast to existing solution, LUKS stores all setup necessary setup information in the partition header, enabling the user to transport or migrate his data seamlessly. (source: http://code.google.com/p/cryptsetup/) Continue reading

CentOS, disk, encryption, LUKS, partition
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Jan 03 2020

Windows RunAs command syntax and examples

Filed under Microsoft

RunAs is a very useful command on Windows OS. This command enables one to run a command in the context of another user account. One example scenario where this could be useful is: Suppose you have both a normal user account and an administrator account on a computer and currently you are logged in as normal user account. Now you want to install some software on the computer, but as you do not have admin privileges you can’t install the same from the current account. One option is to switch user and login as administrator. Instead, you can do the same by simply using runas command. You just need to launch the installer from command prompt using runas command and by providing administrator login id and password. Continue reading

batch, RunAs, Windows
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Dec 11 2019

Skype for Business Server 2019 Monitoring Reports Error: Cannot get the ReportServerWebService URL

Filed under Fixes, Microsoft, Skype for Business

When deploying a recent Skype for Business Server 2019 deployment, I came across an issue when installing monitoring reports on a server. In previous editions of SQL Server, SQL Server Reporting Services (SSRS) was installed and configured by default. With the release of SQL Server 2017, this is now a seperate download that only installs the service. After installing SSRS, the Report Server Web Service/Report Manager in Reporting Services Configuration Manager needed to be configured.