Generate a Certificate Signing Request(CSR) with OpenSSL / Linux



Compile FFmpeg + kxmovie (Xcode 7.3, iOS SDK 9)




Convert PDF to Images in Linux via Command Line

program to convert PDF files into HTML, XML and PNG images


Debian User install pdftohtml using following command:

Red Hat / Fedora user install pdftohtml using following command:

More details:

Setup Asterisk server for telephone validation and cleaning

Prepare a computer with PCI slot

Consider the cost and compatibility, normally I will use Dell desktop or server.

Install telephony interface cards into your computer

Telephony interface cards are PCI or PCI Express expansion cards that connect computers running Asterisk directly to legacy phone lines, phones and phone systems. The cards convert the legacy signaling and media into Asterisk’s internal formats.

I chosen Digium cards, because Asterisk is provided by Digium. A lot of cheaper alternative cards, I just don’t want to facing compatible issue.

More details for telephony interface cards:

Digium telephony interface cards products:

Download and install AsteriskNOW

Simple, just refer to this link:


  1. Login FreePBX Administration via http://<server-ip>
  2. Update Connectivity > DAHDi Config > Global Settings
    • Select Language: <your preferred language>
    • Enable Busy Detect: Yes
    • Other Global Dahdi Settings: callprogress = yes
  3. Update Connectivity > DAHDi Config > System Settings
    • Tone Region: <select your country or compatible>
  4. Update Connectivity > DAHDi Config > Modprobe Settings
    • Opermode: enable, <select your country or compatible>
  5. Click save config andRestart  Dahai and asterisk
  6. Update Settings > Advanced Settings
    1. Country Indication Tones: <select your country or compatible>

Test Asterisk Manager

Default Asterisk Manager User: admin
Default Asterisk Manager Password: amp111

Dialplan for Asterisk Manager

File: /etc/asterisk/extensions_custom.conf



This package contains a Whois (RFC954) library for PHP. It allows a PHP program to create a Whois object, and obtain the output of a whois query with the lookup function.

The response is an array containing, at least, an element ‘rawdata’, containing the raw output from the whois request.

In addition, if the domain belongs to a registrar for which a special handler exists, the special handler will parse the output and make additional elements available in the response. The keys of these additional elements are described in the file

It fully supports IDNA (internationalized) domains names as defined in RFC3490, RFC3491, RFC3492 and RFC3454.

It also supports ip/AS whois queries which are very useful to trace SPAM. You just only need to pass the doted quad ip address or the AS (Autonomus System) handle instead of the domain name. Limited, non-recursive support for Referral Whois (RFC 1714/2167) is also provided.


phpWhois requires PHP 5.3 or better with OpenSSL support to work properly.

Without SSL support you will not be able to query domains which do not have a whois server but that have a https based whois.


Unable to start firewalld, Active: failed (Result: timeout)


Try to start firewalld service via the following command

but get the following error after few seconds no response:


Execute the following command to restart firewalld service


How to Install NGINX and PHP 7.3 with PHP-FPM on RHEL/CentOS 7

Basic Server Setup

Setup Default PHP Version


Update Configuration

Create Virtual Hosts

Setup Firewall (Optional)

SELinux Settings (Optional for SELinux enabled)

Reboot after Setup

How to Install MySQL 8.0 on RHEL/CentOS 7

Basic Server Setup

Setup MySQL 8.0

Setup Firewall (Optional)

Reboot after Setup

Optional Settings for MySQL 8.0

Disable MySQL Strict Mode


Fix MySQL Password Expired

To establish a global policy such that passwords never expire.

Update /etc/my.cnf