The Kalenfy blog
Security, in plain English
Guides on SPF · DMARC · DNSSEC & more — then scan your site free
Guides & checklists
27 June 2026
What Is Business Email Compromise (BEC)?
Business email compromise (BEC) — CEO fraud and fake-invoice scams — costs companies billions. Here's how BEC attacks work and the layered defences that stop them. Free domain check.
Guides & checklists
27 June 2026
What Is an SSL Certificate? (And Do You Need One?)
An SSL/TLS certificate is what puts the padlock and HTTPS on your site, encrypting traffic and proving your identity. Here's what it is, the types, how to get one free, and common errors.
DNS & domain security
27 June 2026
What Is a TXT Record? (And Why It Matters)
A TXT record stores text in your DNS — and it's where SPF, DKIM and DMARC live. Here's what TXT records are, how to add them, and common mistakes to avoid. Free check included.
DNS & domain security
27 June 2026
What Is a Subdomain? (And How to Keep It Secure)
A subdomain is a prefix on your domain like blog.example.com or shop.example.com. Here's what subdomains are, how they work, and the security risks to watch — with a free check.
Email authentication
27 June 2026
SPF Record Examples (Copy-Paste for Common Setups)
Need an SPF record? Here are copy-paste SPF examples for Google Workspace, Microsoft 365, third-party senders and parked domains — plus the syntax explained. Free check.
Fixes & troubleshooting
27 June 2026
How to Get Off an Email Blacklist
Your email is being blocked because your domain or IP is on a blacklist. Here's how to check which one, fix the cause, request delisting, and stop it happening again. Free check.
Guides & checklists
27 June 2026
What Is CSRF (Cross-Site Request Forgery)?
CSRF tricks a logged-in user's browser into making a request they didn't intend — changing a password or making a payment. Here's how it works and how to prevent it, in plain English.
Email authentication
27 June 2026
DKIM Selector Explained (And How to Find Yours)
A DKIM selector tells receivers which public key to use to verify your email. Here's what a selector is, how to find yours, and why it matters — with a free check of your domain.
DNS & domain security
27 June 2026
How to Check Your DNS Records (Free & Easy)
Want to see your domain's DNS records — SPF, DMARC, MX and more? Here's how to check them three ways, what each should look like, and how to spot problems. Free scan included.
Guides & checklists
27 June 2026
What Is Cross-Site Scripting (XSS)?
Cross-site scripting (XSS) lets attackers run malicious scripts on your site, stealing data from your visitors. Here's how it works and how to prevent it, in plain English.