Useful links

Here is a list of useful links that I think it can be useful when having specific trouble.

Linux tutorials site:

  3. – ex. How to block or sinkhole domains in BIND


  1. RHEL 7 Security Guide – Chapter 5. Using Firewalls
  2. Dynamic firewall with firewalld
  3. Introduction to Firewalld Basics
  4. How to Mount a NTFS Drive on CentOS / RHEL / Scientific Linux
  5. Setting Up “NTP (Network Time Protocol) Server” in RHEL/CentOS 7
  6. Setting Up Logrotate on RedHat Linux
  7. VMware: Timekeeping best practices for Linux guests
  8. Adding a New Disk Drive to an RHEL 6 System
  9. How to Create Partition on Linux for >2TB Size using Parted GPT
  10. How to Install and Configure Bind Chroot DNS Server on CentOS 6.3 x86_64
  11. Extend the size of ext3 partition online in a virtual machine
  12. How to Increase the size of a Linux LVM by expanding the virtual machine disk
  13. Install Oracle Java JDK/JRE 7u25 on Fedora 19/18, CentOS/RHEL 6.4/5.9
  14. Install NVIDIA Drivers in RHEL/CentOS/Fedora and Debian/Ubuntu/Linux Mint
  15. Linux Directory Structure and Important Files Paths Explained
  16. Shell Scripting
  17. How to Create a Centralized Log Server with Rsyslog in CentOS/RHEL 7
  18. How To Centralize Logs with Rsyslog, Logstash, and Elasticsearch on Ubuntu 14.04
  19. Red Hat Enterprise Linux Documentation
  20. Red Hat / CentOS IPv6 Network Configuration
  21. 29 Practical Examples of Nmap Commands for Linux System/Network Administrators
  22. Red Hat Enterprise Linux 7 Security Guide: 4.5. Using Firewalls
  23. Introduction to FirewallD on CentOS
  24. Introduction to Firewalld Basics
  25. CentOS Repositories
  26. Mega backup: copies in the cloud in GNU / Linux
  27. How To Create a systemd Service in Linux (CentOS 7)
  28. Useful SystemD commands (hints for systemctl or systemctl vs chkconfig and service)
  29. CentOS 7 – The perfect desktop guide
  30. CentOS 7 – The perfect desktop, second guide!
  31. How to configure multiple instances of sshd in RHEL 7
  32. Setting Up grub2 on CentOS 7
  33. How To Set Up Multi-Factor Authentication for SSH on CentOS 7
  34. adcli – Easy Way To Join RHEL/CentOS System To Active Directory Domain
  35. Efficient Ways To Read The Log Files In Linux
  36. Reset a lost root password in under 5 minutes
  37. How to install Icinga 2 and Icinga 2 web on CentOS 7?
  38. Using Hurricane Electric free DNS service for slaves, revisited
  39. A sysadmin’s guide to SELinux: 42 answers to the big questions
  40. How to Install, Configure and Use Firewalld in CentOS and Ubuntu
  41. Install Nvidia Drivers on CentOS
  42. VirtualBox Guest Additions on Fedora 29/28, CentOS/RHEL 7.5/6.10/5.11
  43. Install ImageMagick (Image Manipulation) Tool on RHEL/CentOS and Fedora
  44. How to Install Python 3 on CentOS 7
  45. Replacing a failing RAID 6 drive with mdadm

CentOS 8:

  1. How to Disable SELinux on CentOS 8
  2. How to Add Swap Space on CentOS 8
  3. How To Add Swap Space on CentOS 8
  4. Secure Apache with Let’s Encrypt on CentOS 8
  5. How to Install PHP on CentOS 8
  6. How To Enable and Install EPEL Repo on CentOS 8.x

Let’s Encrypt:

  1. Using Let’s Encrypt DNS-01 challenge validation with local BIND instance


  1. Run MySQL Querys with Powershell

DNS Tools:

  1. DNS Check
  2. ZoneCheck
  3. DNSstuff
  4. intoDNS
  5. How to Find DNS (Domain Name Server) Records On Linux Using the Dig Command


  1. SQL Indexing and Tuning e-Book


  1. IPv4/IPv6 subnet calculator
  2. How to install phpIPAM on CentOS 7


  1. Online regex tester and debugger: JavaScript, Python, PHP, and PCRE


  1. Using Office 365 as a Smart Host with Postfix
  2. How to rewrite outgoing address in Postfix

Microsoft Office:

  1. Tools to manage Office 2013 volume activation

Windows 10:

  1. How to Uninstall Programs on Windows 10


  1. SAML Developer Tools


  1. [How to] Whitelist Cloudflare IP’s in Wordfence
  2. Protect Your Sites from the EU Cookie Law


  1. The most important Firefox command line options


  1. How to install Tomcat 9 on CentOS 7


  1. How To Create an SSL Certificate on Apache for CentOS 7
  2. Generating a Self Signed SSL Certificate in RHEL/CentOS 7
  3. Qualys SSL Server Test

Fiber Optics:

  1. Picking the right fiber connector – PC, UPC or APC


  1. How to Back Up and Copy PuTTY Sessions and Settings to Another PC
  2. Guide: PuTTY and SSH Key-Based Authentication (Windows)
  3. Saving your PuTTY username and password in a Windows Shortcut


  1. Redirect HTTP to HTTPS in Apache
  2. Secure Apache with Let’s Encrypt on CentOS 8