ServerRecords
Articles
Practical guides on DNS, email authentication and domain security.
DNS Record Types, Explained
A practical tour of every DNS record you will actually touch — A, AAAA, CNAME, MX, TXT, SRV, CAA, the DNSSEC set and the modern HTTPS record — with syntax, gotchas and when to reach for each.
Read →llms.txt: Writing the File AI Crawlers Read First, and Checking Yours
What to put in an llms.txt file, how it differs from robots.txt and sitemap.xml, the habits worth keeping, and exactly what the ServerRecords check confirms.
Read →Checking DNSSEC: How the Chain of Trust Works and Where It Breaks
A practical guide to DNSSEC - how ZSK, KSK, DS, RRSIG and DNSKEY records form a chain of trust, why domains break, and how to check your status.
Read →Reading DMARC Reports: Turn Raw XML Into a Path to p=reject
DMARC aggregate reports arrive as compressed XML nobody can read by hand. Learn how to parse them, spot spoofers, and safely move your domain to p=reject.
Read →PTR Records and Reverse DNS: What They Are and Why Your Mail Depends on Them
How reverse DNS and PTR records work across IPv4 and IPv6, who actually controls them, and why mail servers use FCrDNS to decide whether to trust your IP.
Read →BIMI Records Explained: Getting Your Logo to Show Up in the Inbox
How BIMI puts your verified logo next to your emails, why it depends on strict DMARC, and how to read your BIMI DNS record and catch the usual setup mistakes.
Read →Mapping Subdomains with Certificate Transparency Logs
How the CT Subdomain Resolver reads public certificate logs to find forgotten subdomains, resolve their live IPs, and audit your real attack surface.
Read →MTA-STS: Forcing Encrypted SMTP, and How to Check It Is Actually On
MTA-STS turns opportunistic SMTP encryption into an enforced policy. Here is how the DNS record and policy file work, and how to verify both are live.
Read →SPF Flattening: How to Beat the 10-Lookup Limit Without Breaking Email
Too many DNS lookups in your SPF record triggers PermError and sends legitimate mail to spam. Learn how SPF flattening works, when to use it, and its risks.
Read →HSTS: Closing the One HTTP Connection That Can Still Get You Stripped
Even with HTTPS and a redirect, the first plain HTTP request is a weak spot. Here is how HSTS closes it, what each directive does, and how to check yours.
Read →Reading Email Headers: How to Trace a Message and Spot a Fake
Learn to read raw email headers, trace a message hop by hop, check SPF/DKIM/DMARC results, and catch spoofing with the ServerRecords Mail Header Analyzer.
Read →Reading a Domain's Registration Record: A Practical Guide to WHOIS and RDAP
What a WHOIS/RDAP lookup actually tells you: registrar, lifecycle dates, nameservers, and EPP status codes — plus why modern records omit the owner's contact details.
Read →SPF, DKIM, and DMARC: A Practical Guide to Email Authentication and Deliverability
How SPF, DKIM, and DMARC work together to prove your mail is genuine, keep it out of spam, and stop spoofing of your domain. A step-by-step setup guide.
Read →Who Owns This IP? Reading ASNs, Registries, and Network Allocations
A plain guide to IP ownership: how ASNs and Regional Internet Registries work, what an IP ownership lookup actually tells you, and where to take it next.
Read →CAA Records: Deciding Which Certificate Authorities Can Speak for Your Domain
A practical guide to DNS CAA records - the issue, issuewild and iodef tags, the critical flag, how CAs climb the domain tree, and how to check yours.
Read →What a Domain Health Check Actually Tells You
One scan covers registration, DNS, HTTPS redirects and security headers. Learn what a domain health check surfaces and why each result matters.
Read →Reading a MAC Address: Vendor, OUI, and the Bit Flags That Matter
Turn a hardware MAC address into a manufacturer name, and learn to read the OUI, the NIC portion, and the bit flags that reveal randomized or spoofed addresses.
Read →Email Health Check: One Lookup for MX, SPF, DMARC, and TLS
Run one domain lookup to see whether your MX, SPF, DMARC, MTA-STS, and TLS-RPT records are configured correctly and where your email is exposed.
Read →Blacklist Lookup: How to Check If Your Mail Server IP Is on a DNSBL
Check your server IP against major DNSBLs, understand how reverse-DNS blacklist queries work, learn why clean IPs get listed, and how to get delisted.
Read →Reading a Domain in One Pass: A Guide to Full DNS Record Lookups
See every DNS record for a domain at once - A, MX, TXT, SPF, DMARC, CNAME, NS, SOA, CAA, SRV and WHOIS - and learn what each one actually does.
Read →Why Length Beats Complexity: A Practical Guide to Strong Passwords
How password entropy actually works, why length matters more than symbols, and how a browser-based CSPRNG generates credentials that never leave your machine.
Read →Picking a RAID Level: Capacity, Redundancy, and the Math Behind It
Compare RAID 0, 1, 5, 6, and 10 by usable capacity, fault tolerance, and efficiency, with the formulas and a worked example, so you can size an array with confidence.
Read →How Long Will That Transfer Really Take? Bits, Bytes, and Bandwidth
Why "1 Gbps, 100 GB, 100 seconds" is wrong, and how to read a transfer-time estimate correctly using bits vs bytes and the gap between bandwidth, throughput, and goodput.
Read →Subnetting Without the Binary Headaches: A Practical CIDR Guide
Understand CIDR prefixes, subnet and wildcard masks, network and broadcast addresses, and usable host ranges for IPv4 and IPv6, without doing the binary by hand.
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