The Kalenfy blog
Security, in plain English
Guides on SPF · DMARC · DNSSEC & more — then scan your site free
DNS & domain security
27 June 2026
Wildcard DNS & Subdomain Takeover: The Hidden Risk
Wildcard DNS and dangling records can let attackers hijack your subdomains for phishing. Here's how subdomain takeover works, the warning signs, and how to check your domain free.
Email authentication
27 June 2026
SPF vs DKIM vs DMARC: What's the Difference?
SPF, DKIM and DMARC explained and compared in plain English — what each does, how they work together to stop email spoofing, and how to check yours. With a free scan.
Fixes & troubleshooting
27 June 2026
Multiple SPF Records: Why They Break Email (and How to Fix It)
A domain can only have ONE SPF record — two breaks email authentication and sends mail to spam. Here's why multiple SPF records fail and how to merge them into one. Free check.
DNS & domain security
27 June 2026
What Is a CAA Record (and How to Add One)?
A CAA record controls which certificate authorities can issue SSL certificates for your domain. Here's what it is, why it matters, and how to add one — with a free check.
Email authentication
27 June 2026
Google & Yahoo Sender Requirements: Are You Compliant?
Since 2024 Google and Yahoo require SPF, DKIM and DMARC to deliver email. Check if your domain is compliant in seconds — and exactly how to fix it if it isn't.
Email authentication
27 June 2026
Why Are My Emails Going to Spam? (And How to Fix It)
Business emails landing in spam? Most of the time it's missing SPF, DKIM or DMARC. Here's how to find the real cause and fix it — with a free scan to check your domain.
Fixes & troubleshooting
27 June 2026
How to Fix SPF “Too Many DNS Lookups” (PermError)
SPF "too many DNS lookups" (PermError) silently breaks your email authentication. Here's how to check your lookup count and fix it — flattening, removing includes, and more.
Email authentication
27 June 2026
Email Spoofing: How Attackers Fake Your Domain (and How to Stop It)
How email spoofing works, why it's so easy without protection, and the three records — SPF, DKIM and DMARC — that stop attackers from sending phishing emails as your domain.
DNS & domain security
27 June 2026
What Is DNSSEC and Why Your Domain Needs It
DNSSEC explained simply: what it is, the DNS spoofing and cache-poisoning attacks it prevents, how to check if DNSSEC is enabled, and how to turn it on for your domain.
Email authentication
27 June 2026
SPF Records Explained: How to Check and Fix Yours
What an SPF record is, how the v=spf1 syntax works, the 10-lookup limit, the most common SPF mistakes (+all, multiple records, softfail) and how to check your SPF for free.