Understanding `dig`: How to Actually Read DNS Query Output
If you've ever stared at the output of dig example.com and only understood half of it, you're not alone. dig (Domain Information Groper) is the tool…
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ISC BIND 9.18.42 Released: Major Milestone for DNS Security
ISC BIND 9.18.42 Released: Major Milestone for DNS Security Meta: ISC’s BIND 9.18.42 hit the open‑source stage on November 5, 2025, delivering a sui…
The SPF redirect trap: why -all can make redirect= useless
The SPF redirect trap: why -all can make redirect= useless SPF records often look simple until you start combining mechanisms and modifiers. One par…
I let a domain expire once. Now I check them all with a script.
A few years back I let a domain lapse. Not a throwaway one either. It was live, had traffic, and I just forgot the renewal date sitting in some regi…
Pushgateway Heartbeat Gotcha: When ndots and NetworkPolicy Silently Eat Your Alerts
A CronJob exits 0, Pushgateway shows a heartbeat metric that hasn't updated in days, and Prometheus fires nothing. Every dashboard is green while th…
SPF record hygiene: the security debt nobody logs
Nobody opens a ticket for an SPF record. There is no alert, no dashboard turning red, no user calling to say that an IP address from a provider the…
How BIMI Inspection Actually Works: DNS Records, Selectors, SVG Logos and DMARC
How BIMI Inspection Actually Works: DNS Records, Selectors, SVG Logos and DMARC BIMI looks simple at first glance: publish a DNS record, point it at…
Debugging VPN DNS Problems: Find the Layer That Is Actually Answering
When DNS starts behaving strangely—a site resolves differently than expected, a recent change does not appear, or two devices disagree—the VPN often…
Tech Talk Augusta — August Meetup Recap
Tech Talk Augusta — August Meetup Recap: DNS, AI, and Solving the Right Problem Our August Tech Talk brought together three very different talks, bu…
DNS Records Explained: A, AAAA, CNAME, MX, TXT, NS, and SRV Records in Modern Internet Infrastructure
In the previous article , we explored how DNS translates human-friendly domain names into machine-friendly IP addresses and how a request travels th…
HELO vs EHLO: Why Your SMTP Greeting Can Hurt Email Delivery
HELO vs EHLO: Why Your SMTP Greeting Can Hurt Email Delivery Your SPF, DKIM, and DMARC records may all look correct while your mail server still int…
SPF passed. DKIM passed. DMARC failed. Nothing is broken.
This header block is where most people's understanding of email authentication falls apart: Authentication-Results : mx.google.com; spf=pass smtp.ma…
Why your DMARC reports never arrive (and why Gmail can't be your rua address)
You published a DMARC record months ago. Every checker says it's valid. No reports have ever arrived, and at some point you stopped thinking about i…
Your SPF record can be valid, published, and completely ignored
There's a failure mode in SPF that produces no error anywhere you'd think to look. Your record is syntactically valid. dig returns it. Your DNS prov…
How to read a DMARC aggregate report without losing your mind
You turned on DMARC, and now a few times a day Google, Microsoft, and a handful of providers you've never heard of email you an XML file. Opened one…
How to Set Up a Free, Full HTTPS Domain Redirect with Cloudflare and Namecheap
If you have ever bought a domain on Namecheap to redirect traffic to your main web app, you might have hit a frustrating wall: Namecheap's free "Dom…
Why SPF Breaks After Adding One More Email Provider
Why SPF Breaks After Adding One More Email Provider Your SPF record may look valid and still produce a PermError . This often happens after connecti…
How to Preview a Website on a New Server Before You Change DNS
Every website migration has the same terrifying moment: you flip the DNS record, and for the next few hours you have no idea whether the new server…
How to Check SPF, DKIM, and DMARC Records in Python
If your app sends email — transactional or marketing — three DNS records decide whether it lands in the inbox or the spam folder: SPF , DKIM , and D…
Split-Horizon DNS: One Name, Two Answers, and the Server Decides by Who's Asking
Originally published at https://blog.pathvector.dev/protocol-lab-dns-views-42-split-horizon/ — part of the free Protocol Lab series. This post is pa…
DNS Round-Robin: The Cheapest Load Balancer Is Three A Records and a Rotating Answer
Originally published at https://blog.pathvector.dev/protocol-lab-dnsrr-41/ — part of the free Protocol Lab series. This post is part of Protocol Lab…
Building a Lightweight DNS Exploration Tool in Python
When building out network enumeration tooling, understanding how domain structures map out is a core skill for any security enthusiast or developer.…
Zero DNS setup with Copilot: what it means for SL devs
The zero DNS configuration demo GitHub just published is being read as "AI does your DNS for you." I read it differently. What GitHub actually showe…
DNS not updating after hosts file change? Fix it in order
You edited the hosts file. The line looks correct. The browser still opens the old site. Do not rewrite the hosts file again yet. Walk the stack in…
Your email passes SPF and DKIM but still fails DMARC. Here's why
Your email passes SPF and DKIM but still fails DMARC. Here's why You set up SPF. You set up DKIM. You send a test message and both come back pass. T…
DNS Propagation Time: How Long Until Your DNS Change Goes Live?
You change the A record for api.example.com from 203.0.113.10 to 203.0.113.20`. Your browser shows the new IP. The deployment dashboard says green.…
I Was Basically Gaslighted Into Learning DNS... and I'm Glad I Was
I have a confession. I was strongly encouraged (read: lovingly gaslighted ) into writing this article. At first, I thought, "Why me? Can't someone e…
Lowering your DNS TTL will not speed up your failover, and here is the data showing why
I spent three months measuring multi-cloud DNS failover for my final-year dissertation. The most useful thing I learned contradicts common advice, s…
DMARC Just Got 3 New RFCs. Your DNS Record Doesn't Need to Change.
If you've ever pasted v=DMARC1; p=reject; into a TXT record and moved on with your life, here's something worth two minutes: the spec behind that re…
97.8% of the top 10,000 domains have no MTA-STS. Here's how to be in the other 2%
Of the 10,000 most-visited domains on the web, 97.8% have no MTA-STS policy at all. Not misconfigured. Not weak. Just absent. I scanned the Tranco t…