Secondary DNS After the 2025-2026 Outages: What Broke and What Helps
Four DNS outages between July 2025 and May 2026 failed in four different places. Here is which of them secondary DNS would have stopped, which it woul…
Category: System Admin
Why IPv6 is it needed: an extraordinary properties
About the IPv6 A little clarification, an IP address is, in fact, the postal address of a device on a network. Each site, smartphone, computer, server…
Ability to switch to a new hard drive without a RAID controller and reboot
If you have a Linux server without a hardware RAID controller that you’d never want to shut down, and one of the disks starts to fail. If a minimum o…
The Crucial Importance of Backup Storage
Backing up data is a process of storing redundant copies of files and directories located on local disks on removable media, usually magnetic tapes. R…
What to do with the growing log files, how not to lose data and save disk space?
During the operation of Unix / Linux systems, administrators face one very widespread problem, but it is not as easy to solve as it seems at first gla…
What is DNS and what is it used for?
What Is DNS DNS is a domain name recognition system for obtaining information about domain names. The domain name system is mainly used to find out th…
Spam Filtering Based on SMTP Header
Spam. Spam is incessant; therefore, each responsible mail administrator should keep up with spam filtering methods based on their headers’ SMTP analys…