Guides, tools and research
Everything you need to understand and improve your domain security posture. Free guides, 18 instant tools, and original research.
UK MSP DMARC Audit: Q1 2026
192 UK MSPs analysed across DMARC, SPF, SSL, DNSSEC, and brand domain protection.
Updated quarterly with fresh data. Downloadable tables and regional breakdowns included.
Showing 51 of 51 resources
Bulk Sender Requirements 2026: Google, Yahoo and Microsoft
What Google, Yahoo and Microsoft require from bulk senders in 2026: SPF, DKIM, DMARC alignment, one-click unsubscribe and spam-rate limits, mapped to the DNS controls that satisfy them.
DMARC for MSPs: Managing Email Security Across Client Domains
An operational playbook for UK MSPs running DMARC across many client tenants: auditing, bulk onboarding, per-client white-label reporting, alignment and pricing that scales.
How to Move from DMARC p=none to p=reject (Step by Step)
A report-driven path from p=none to p=reject: read the aggregate reports, authorise every legitimate sender, then advance to quarantine and reject once the data is clean.
Free DMARC Tools Compared: Checkers, Generators and Report Viewers
An honest map of the free DMARC tool landscape in 2026, what each one really gives you, the limits of free tiers, and when a multi-domain team should move to a paid platform.
DMARC for Parked Domains: Lock Down Non-Sending Domains
How to set up DMARC for a parked domain that never sends email. NULL MX, SPF -all, p=reject and DKIM revocation, with RFC, NCSC and M3AAWG sources.
Best DMARC Monitoring Tools UK 2026
UK-focused 2026 comparison of ShieldMarc, dmarcian, EasyDMARC, PowerDMARC, Valimail, Red Sift and Sendmarc. Pricing, features, data residency and best fit for UK MSPs, multi-domain IT teams, NHS trusts and enterprise.
What We're Building and When You Can Use It
A progress update on the ShieldMarc platform: what we are working on, when we expect to open to the public, and how to start a free trial.
How to Set Up DMARC for Google Workspace
Step-by-step guide to configuring DMARC, SPF, and DKIM for Google Workspace. Protect your domain from spoofing and improve Gmail deliverability.
How to Set Up DMARC for Microsoft 365 (Office 365)
Step-by-step guide to configuring DMARC, SPF, and DKIM for Microsoft 365. Protect your organisation from email spoofing and improve deliverability.
What is BIMI? Brand Indicators for Message Identification Explained
How BIMI displays your verified logo in Gmail, Apple Mail, and Yahoo, and what a VMC actually costs.
DMARC p=quarantine vs p=reject: Which Policy Should You Use?
When to pick quarantine, when to pick reject, and how to move between them without breaking mail flow.
DMARC for the NHS and UK Public Sector: A Post Mail Check Guide
How NHS trusts, councils, and gov.uk bodies can replace NCSC Mail Check with a UK owned, EU hosted platform.
Our Mission: AI Tools, Open to All
Why we built ShieldMarc with free AI-powered tools at its core, and what we believe about access, protection, and the future of email security.
How ShieldMarc Threat Detection Works
Every DMARC report row is evaluated by a multi-signal scoring engine and AI evaluation to separate genuine threats from noise. Here is how it works.
Why Modern DMARC Monitoring Costs a Fraction of Legacy Tools
Legacy DMARC platforms carry years of technical debt. We built ShieldMarc from scratch in 2026 with modern tooling and zero bloat.
What is DMARC? A Plain English Guide
DMARC explained for IT teams. What it does, how it works, and why you need it.
SPF vs DKIM vs DMARC: What's the Difference?
How SPF, DKIM, and DMARC work together to protect your domain from spoofing.
Understanding DMARC Reports: RUA and RUF Explained
How to read and act on DMARC aggregate and forensic reports.
SPF Hard Fail vs Soft Fail: Why ~all Is Safer with DMARC
When to use -all vs ~all in your SPF record and how DMARC changes the equation.
How to Fix SPF Too Many DNS Lookups
Diagnose and fix the 10 DNS lookup limit in SPF records.
NCSC Mail Check Has Retired: What UK Organisations Should Do Now
What the NCSC Mail Check retirement means and how to replace it.
SSL Certificate Monitoring: What to Check and When
Avoid certificate expiry incidents with proactive SSL monitoring.
What is MTA-STS and TLS-RPT? Securing Email in Transit
How MTA-STS enforces TLS for inbound email and TLS-RPT captures delivery failures.
What is DNSSEC? How DNS Signing Protects Your Domain
How DNSSEC prevents DNS spoofing and cache poisoning attacks.
CAA Records Explained: Control Who Issues Your SSL Certificates
Use CAA records to restrict which certificate authorities can issue certs for your domain.
DNS Record Types Explained: A, AAAA, MX, TXT, CNAME and More
A guide to every common DNS record type and what it does.
Domain Expiry and WHOIS: How to Protect Your Registration
Prevent domain hijacking and accidental lapses with registration monitoring.
Protecting Your Brand from Lookalike Domains
Detect and defend against typosquatting and brand impersonation domains.
How to Create SPF, DKIM, and DMARC Records: Step-by-Step
A step-by-step walkthrough for setting up email authentication from scratch.
How to Set Up DKIM: Step-by-Step for Every Email Provider
Provider-specific DKIM setup guides for Google Workspace, Microsoft 365, SendGrid, Mailchimp, and more.
ShieldMarc vs EasyDMARC
A straight comparison for UK MSPs: pricing, message volume, AI model, posture and support.
ShieldMarc vs dmarcian
A straight comparison for UK MSPs: pricing, message volume, AI model, posture and support.
ShieldMarc vs Valimail
A practical alternative to enterprise-priced DMARC. Published pricing, self-serve onboarding, 90-day trial.
Security Grade
Run 15 security checks and get an A+ to F grade.
SPF, DKIM & DMARC Checker
Check your DMARC policy, SPF record, and DKIM selectors in one scan.
SSL Certificate Checker
Inspect certificates, expiry dates, and chain validity.
DNS Lookup
Query any DNS record type instantly.
SPF Flattener
Resolve SPF includes to a flat list of IPs.
Lookalike Domain Scanner
Detect typosquat and impersonation domains.
DNSSEC Checker
Verify DNSSEC signing on any domain.
MTA-STS Checker
Check MTA-STS policy and TLS enforcement.
TLS-RPT Checker
Verify TLS-RPT reporting records.
CAA Checker
Inspect CAA records and certificate issuance restrictions.
Domain Expiry Checker
Check domain registration status and expiry dates.
WHOIS Lookup
Query domain registration and ownership data.
DMARC Record Generator
Build a valid DMARC record in seconds.
SPF Record Generator
Create an SPF record with your email providers.
DKIM Record Generator
Generate a DKIM DNS record for your domain.
CAA Record Generator
Build CAA records to restrict certificate issuance.
DMARC Report Viewer
Upload and parse DMARC aggregate XML reports.
Email Header Analyzer
Paste email headers and see authentication results, routing hops, and delays.