Spotting a Rogue Device on a Segmented VLAN
An unfamiliar MAC address showed up on your restricted VLAN. Confirm whether a rogue device actually crossed the boundary before you assume intrusion.
Network Security: Firewalls, Ports & Filtering | NetworkCheckr
Network security fundamentals — firewalls, port numbers, traffic filtering, certificates, and practical steps to lock down your network.
Unknown Device on Your Network? How to Identify It (and When to Worry)
Found an unfamiliar device on your Wi-Fi? Here’s how to identify it by MAC vendor, rule out your own gear, and know when to actually worry.
Untrusted Root Certificate Popup in Chrome: Is My Computer Hacked?
An untrusted root certificate popup in Chrome is alarming, but rarely means malware. Here’s what causes it, how to inspect the certificate, and when to actually worry.
Best Network Security Software for 2026
Looking for the best network security software in 2026? You do not need one giant suite. The right setup mixes a few focused tools for passwords, VPN, DNS, and antivirus, and several are free.
How to Choose a Web Hosting Provider: A Security-First 2026 Guide
Choosing a web hosting provider? Weigh security first, then budget. This guide covers the features that matter, names vetted budget, mid-range, and premium picks, and shows how to test any host yourself.
SPF, DKIM, and DMARC Explained: How They Work Together
Want SPF, DKIM, and DMARC explained without the vendor sales pitch? Each protocol solves part of email spoofing. Here is what they do, how they work together, and what to set up first.
What Is a DNS Blacklist? (And How to Get Off One)
Need to remove your IP from an email blacklist? Spamhaus, Barracuda, and SpamCop each have different processes. Here is what a DNS blacklist actually is, why SORBS no longer matters, and the steps that work.
How to Set Up SPF and DMARC Without Breaking Email
Need to set up SPF and DMARC without breaking email delivery? The safe order matters more than the records themselves. Here is the staged playbook — inventory senders first, publish in order, monitor before enforcing.
How SSL Certificates Work (And What to Do When They Expire)
Want to know how SSL certificates work without the marketing fluff? They prove a server’s identity using a chain of trust. Here is what changed in March 2026, and what to do when one expires.
What Is a Firewall? Ports, Rules, and Traffic Filtering
TL;DR — The Short Version A firewall monitors and controls network traffic based on a predefined set of rules. It sits between trusted and untrusted networks. Decisions come from packet headers. Source and destination IP, port numbers, and protocol determine whether traffic is allowed, denied, or dropped. Types range from simple to deep. Stateless packet … Read more