DNS

• DNS “Temporary failure in name resolution”: the 5 root causes and the fix order
• Reverse DNS (PTR): Why Your Email Suffers and How to Fix rDNS Correctly
• Fix Proxmox apt update Failures: DNS, Repos, and GPG Keys (Step-by-Step)
• DNS REFUSED Responses: ACLs and Policies That Block You (and How to Correct Them)
• DNS Wildcard Records: The Convenience That Quietly Breaks Things (and Fixes)
• Split-horizon DNS: Make LAN names resolve without breaking the public internet
• DNS Across Offices: Make Hostnames Resolve Everywhere (Windows + Linux)
• DNS: BIND9 zone won’t load — the top syntax mistakes and fast fixes
• Debian 13: DNS over TLS/HTTPS — enable it without breaking enterprise networks (case #51)
• Docker Service Discovery Fails: DNS and Network Aliases Done Right
• DNS Monitoring: Alert Before Users Notice (Simple, Effective Checks)
• DNSSEC Fails Randomly: Debugging Validation Errors Without Panic
• DNS Changes Not Visible: Which Caches to Flush (and Which Not to Touch)
• DNS: NXDOMAIN vs SERVFAIL — the quick way to tell what’s broken (and fix it)
• Ubuntu 24.04: DNS caches lie — flush the right cache (and stop flushing the wrong one) (case #86)
• Ubuntu 24.04: DNS caches lie — flush the right cache (and stop flushing the wrong one) (case #26)
• DNS: Unbound caching resolver — set it up in 15 minutes (and avoid the common trap)
• DNS Cache Poisoning Basics: Harden Your Resolver Without Overengineering
• dnsmasq Cache + DHCP: A Clean Config That Doesn’t Fight Your System
• DNS: Dig/drill power moves — commands that answer 90% of DNS mysteries
• DNS EDNS0 Fragmentation: The Hidden Cause of “Works on Wi‑Fi, Fails on LTE”
• Debian 13: SSH is slow to log in — DNS and GSSAPI fixes that speed it up instantly (case #5)
• Local DNS for VPN Users: Stop DNS Leaks and Split Routing Failures
• DNS load spikes: rate-limit and survive attacks without downtime
• Docker: DNS inside containers is broken — systemd-resolved fixes that stick
• Ubuntu 24.04 “Temporary failure in name resolution”: stop guessing and fix DNS the right way
• WireGuard DNS Not Working Through VPN: Correct DNS Setup on Linux and Windows
• DNS: MTU Issues Can Break DNS — How to Prove It and Fix It
• Docker DNS Caching Lies: Flush the Right Cache (Inside vs Outside Containers)
• Active Directory over VPN: What Breaks First (DNS, Time, Ports) and How to Fix It
• DNS over HTTPS and DNS over TLS: privacy without breaking corporate networks
• Ubuntu 24.04: VPN breaks DNS — fix resolvers and routes in the correct order (case #52)
• DNS: Your DNS “works” but apps still fail — the caching layers you forgot exist
• DNS Slow Lookups on Linux: Fix systemd-resolved the Right Way
• Docker Desktop Networking Weirdness: LAN Access, Ports, and DNS Fixes That Actually Work
• Docker Pull Is Painfully Slow: DNS, MTU, and Proxy Fixes That Actually Work
• Debian 13: DNS split-horizon gone wrong — fix internal names without breaking the internet (case #33)
• DNS TTL Mistakes That Haunt Migrations — How to Set TTL Like a Pro
• DNS “bogus/validation failed”: fixing upstream DNSSEC issues the practical way
• Ubuntu 24.04: systemd-resolved breaks Docker DNS — fix without disabling everything
• Email: Mixed DNS records — the typo that kills delivery (and the fix)
• DNS SERVFAIL from Upstream: How to Prove Your Provider Is the Problem
• Debian 13: SSH is slow to log in — DNS and GSSAPI fixes that speed it up instantly (case #65)
• rDNS/PTR Missing: The Boring DNS Fix That Saves Email Deliverability
• Debian 13 Split DNS for VPN and LAN: a clean setup that won’t break after reboot
• DNS CNAME Chains: When They Become a Performance and Reliability Problem