📝 Whose.Domains Blog

All Posts Domain Tools Domain Investing Guides News

📄

security

Passive DNS Explained: How to Investigate Domain History and Detect Malicious Infrastructure

Passive DNS is a powerful technique for tracking the historical IP addresses, nameservers, and records associated with a domain. This article explains what passive DNS is, how it differs from active lookups, and how you can use it to investigate domain history, spot malicious infrastructure, and make safer acquisition decisions.

Sep 7, 2026 30 views

📄

dns

DNS SVCB and HTTPS Records Explained: How to Advertise HTTP/3 and Improve Connection Performance

DNS SVCB and HTTPS records (defined in RFC 9460) let websites advertise modern protocols like HTTP/3 and QUIC directly from the DNS layer, trimming connection latency and improving resilience. This article explains how they work, when to use them, and how to implement them correctly with practical examples.

Sep 4, 2026 29 views

📄

dns

NSEC and NSEC3 Records in DNSSEC: How They Prevent Zone Walking and Authenticate Denial of Existence

This article explains how DNSSEC uses NSEC and NSEC3 records to authenticate “denial of existence” responses. We’ll compare the two mechanisms, show how NSEC enables zone walking while NSEC3 mitigates it, and share practical tips for securing your own domains.

Aug 31, 2026 30 views

📄

security

CAA Records Explained: How to Restrict Which Certificate Authorities Can Issue SSL/TLS Certificates for Your Domain

CAA (Certificate Authority Authorization) records are DNS records that let you control which Certificate Authorities can issue SSL/TLS certificates for your domain. This article explains the syntax, walks through real-world examples, and shares actionable tips to avoid common pitfalls.

Aug 28, 2026 57 views

📄

security

DNSSEC Signing Explained: How to Protect Your Domain from DNS Spoofing and Cache Poisoning

This article explains how DNSSEC signing works, why DNS spoofing and cache poisoning are such dangerous threats, and how digital signatures create a verified chain of trust. It includes real-world attack examples and practical, step-by-step tips for enabling and monitoring DNSSEC on your own domain.

Aug 25, 2026 33 views

📄

dns

DNS CNAME Flattening Explained: How to Use Apex Domains with CDNs and Cloud Services

CNAME flattening lets you point your root domain (like example.com) to CDNs and cloud services by resolving CNAME records at the DNS provider level and returning standard A/AAAA records. This article explains how it works, why it matters, and how to avoid common pitfalls like email conflicts and SSL misconfigurations.

Aug 22, 2026 63 views

📄

dns

EDNS Client Subnet Explained: How It Improves CDN Performance and DNS Accuracy

EDNS Client Subnet (ECS) is a DNS extension that carries partial client IP information to authoritative name servers, enabling more precise geo-routing and better CDN performance. This article explains the mechanism, real-world impact, and practical configuration steps to get ECS working correctly across your DNS stack.

Aug 13, 2026 50 views

📄

dns

SPF, DKIM, and DMARC Explained: How to Set Up Email Authentication to Avoid Spam and Spoofing

Email authentication protocols SPF, DKIM, and DMARC work together to verify sender identity, protect your domain from spoofing, and keep your messages out of the spam folder. This guide explains how each protocol works, walks through a practical setup sequence, and highlights the most common mistakes so you can get your email infrastructure right the first time.

Aug 7, 2026 66 views

📄

dns

How to Use GeoDNS and Server Load Balancing to Improve Website Performance and Availability

GeoDNS and server load balancing are two complementary techniques that keep websites fast and online even under heavy traffic. GeoDNS sends visitors to the nearest available server based on their location, while load balancing spreads the workload across multiple machines to prevent any single server from becoming a bottleneck. This article explains how to combine both for maximum performance and reliability.

Aug 4, 2026 49 views

📄

security

DNS Response Policy Zones (RPZ): How to Use Them to Block Malware and Phishing Domains

DNS Response Policy Zones (RPZ) give network administrators a powerful, DNS‑level way to block malware and phishing domains before they ever reach their users. This article explains how RPZ works, provides step‑by‑step setup tips, shares a real‑world example, and offers actionable advice for integrating RPZ into your security stack.

Jul 31, 2026 91 views

📄

dns

What Are Glue Records in DNS and When Do You Need Them?

Glue records are essential DNS records that prevent circular dependencies when a domain's nameservers are within the same domain. This article explains what glue records are, how they work, and when you need them, with practical examples and tips for domain owners and administrators.

Jul 22, 2026 71 views

📄

security

How to Use SSHFP Records in DNS to Verify SSH Host Keys and Prevent Man-in-the-Middle Attacks

SSHFP (SSH Fingerprint) records in DNS let clients automatically verify SSH host keys before connecting, blocking man-in-the-middle attacks. This article explains how to generate and publish SSHFP records, configure clients to verify them automatically, and why combining SSHFP with DNSSEC provides strong security for remote server access.

Jul 16, 2026 212 views

1 2 3 Next →