Articles & Guides
Useful resources for web developers and system administrators
Networking
What Is 0.0.0.0? Listen Address, Default Route and Hosts File
What 0.0.0.0 means: listen on all interfaces, the 0.0.0.0/0 default route, DHCP and hosts-file blocking. How it differs from 127.0.0.1, with ss and netstat checks.
Tools
Wayback Machine: How to See Old Versions of a Website
Use the Wayback Machine at web.archive.org to see how a site looked on any date, list archived URLs with the CDX API, save a page or request removal.
Networking
Telnet Port Check: Test Open Ports on Windows, Linux, macOS
How to check a port with telnet: enable the Windows client, use Test-NetConnection or nc, and read refused vs timeout results. Includes a command cheat sheet.
Domains
.su Domain: Soviet Union Country Code Still Active in 2026
.su is the country code TLD assigned to the USSR in 1990, still active and run by Russia's ROSNIIROS. Who can register it, .su vs .ru, the risks.
Networking
192.168.1.1 Router Login: Find the IP, Sign In, Fix Errors
How to log in to your router at 192.168.1.1: find the real gateway IP on any OS, default logins by brand and ISP, and a fix table for when the page won't load.
Security
Russia's Personal Data Operators Registry: Check and File
How Roskomnadzor's personal data operators registry works: who must notify under 152-FZ Article 22, how to search by INN, and how to file or update an entry.
Security
OSINT for Domains and Websites: What to Check and How
OSINT for websites explained: what WHOIS/RDAP, DNS, crt.sh certificate logs, IP and ASN data, reverse IP and the Wayback Machine reveal, with commands and tools.
DNS
nslookup Command: How to Use It and Read the Output
How to use nslookup on Windows, Linux and macOS: query a specific DNS server, look up MX, TXT, NS and SOA records, read the output and fix common errors.
Infrastructure
IMAP vs POP3: Differences, Ports and Which One to Use
IMAP keeps mail on the server and syncs every device; POP3 downloads it to one computer. Comparison table, ports 993 and 995, provider settings and test commands.
Domains
example.com: Who Owns It and Is test@example.com Real?
No company owns example.com: IANA holds it for documentation (RFC 2606). Nobody can register it, and test@example.com receives no mail.