Skip to main content
New SPF lookups must resolve in milliseconds — why a DMARC tool's add-on isn't enough Learn Why → →
Knowledge Base

Blog

Expert guides on SPF, DKIM, DMARC, and email security.

Foundational 14 min

IP Address Generator: Create Random IP Addresses for Free

In a digital landscape where every click can reveal your location or personal information, protecting your privacy is more important than ever.

Foundational 19 min

IP Lookup: Discover Your IP Address Location and Details

In today’s digital landscape, your IP address is more than just a line of numbers; it’s like a digital identity that reveals where you are and who you’re with.

Intermediate 5 min

The ‘unsubscribe’ button is a new security risk; consider a different approach

We are often told to simply ‘unsubscribe’ from newsletters, shopping emails, and similar lists, as it shrinks our digital footprint, prevents soft spam.

Intermediate 13 min

DKIM Authentication: A Complete Guide to Secure Email Deliverability

In the digital age, where nearly everyone relies on email for communication, ensuring your messages reach their intended recipients without being hijacked.

Intermediate 9 min

Common SPF Record errors (and how to fix them): Null values, multiple includes, and network solutions issues explained

The three most common SPF errors are multiple records on the same domain (PermError), null values from broken include chains (counted as void lookups), and Network Solutions DNS panels stripping quotes from TXT values. Each has a specific RFC-compliant fix.

Foundational 5 min

What does the ‘null’ value mean in an SPF record?

Imagine setting up an SPF record to protect your domain, only to realize it’s as good as not having one!

Intermediate 13 min

SPF for Subdomain: A Complete Guide to Configuration and Security

Each subdomain that sends email needs its own SPF TXT record - subdomains do NOT inherit SPF from the parent domain. Learn how to configure, test, and maintain SPF records for subdomains like mail.example.com, sales.example.com, and support.example.com.

Intermediate 5 min

How to safeguard your business against Vendor Email Compromise (VEC)?

Vendor Email Compromise (VEC) or financial supply chain compromise is a type of threat attack where cybercrooks spoof or impersonate the email account of a.

Advanced 14 min

SPF Compression: A Comprehensive Guide to Benefits and Techniques

SPF Compression and Its Role in Email SPF compression is more than just a technical buzzword; it’s an essential practice that enhances the functionality of.

Intermediate 5 min

The New Zealand government’s new DMARC requirements for email security

The New Zealand government recently published its Secure Government Email (SGE) framework.

Advanced 12 min

Multiple SPF Records: Essential Configuration for Email Authentication

Can You Have Multiple SPF Records? The crux of the matter is that you cannot have multiple SPF records for a single domain.

Intermediate 6 min

How often should you audit your SPF record, and what should you look for?

An SPF record is the primary authorization layer that determines whether your SPF configuration will be effective or let any domain send emails on your behalf.

Foundational 6 min

Understanding SPF mechanisms: a, mx, ip4, and include

SPF has 8 mechanisms defined in RFC 7208: all, include, a, mx, ptr, ip4, ip6, and exists. The four most common are ip4 (authorize a specific IP), a (authorize the domain's A record), mx (authorize the domain's MX records), and include (delegate to another SPF record). Learn the exact semantics and lookup cost of each.

Intermediate 13 min

Mimecast SPF: Setup Guide for Effective Email Protection

In a time where our inboxes overflow with messages, not all of them are as innocent as they seem.

Foundational 3 min

A simple explanation of DMARC compliance laws

"The most misunderstood thing about DMARC is that SPF passing is not enough - the domains have to align," says Brad Slavin, General Manager of DuoCircle.

Intermediate 5 min

Handling common SPF errors the right way

SPF is a sensitive email authentication protocol; it requires all details to be correct to produce accurate authentication results.

Intermediate 14 min

Proofpoint SPF Record: The Essential Email Security Configuration Guide

In a world where email is the primary mode of communication for businesses and individuals alike.

Foundational 12 min

How to Check SPF Record on MXToolbox for Email Validation

In the world of email communication, getting your messages to land in inboxes instead of spam folders is crucial.

Advanced 7 min

Invisible SPF failures: How misconfigured DNS entries are costing enterprises millions!

There’s a common misconception among domain owners when it comes to email authentication protocols - we have configured SPF, DKIM, and DMARC.

Intermediate 6 min

6 Best practices for maintaining an SPF record

Threat actors seek ways to impersonate credible companies and their representatives to send phishing emails on their behalf.

Intermediate 5 min

How to fix “550; 5.7.15 Access Denied” rejections?

Microsoft has always prioritized email security, and in pursuit of this goal, it mandated that all bulk senders properly authenticate their messages.

Intermediate 5 min

DMARC and anti-spam aren’t the same!

With around 3.4 billion spam emails sent daily, securing inboxes has become more challenging than ever.

Intermediate 6 min

Optimizing Email Deliverability: Strategies for Success

Your carefully crafted marketing campaign just launched, complete with compelling subject lines and perfectly timed send schedules.

Intermediate 5 min

Understanding the relevance of Sender Policy Framework (SPF) in 2025

Sender Policy Framework (SPF) is an email authentication protocol designed to prevent email spoofing - a common tactic in spam and phishing attacks.

Intermediate 15 min

Kitterman SPF Check: A Comprehensive Guide to Performance Analysis

In the digital landscape, email is still one of the primary ways we communicate, whether for business proposals or casual chats.

Intermediate 15 min

KnowBe4 SPF Record: How to Set Up for Maximum Email Security

In an age where email remains a primary communication tool for businesses, the dangers lurking in our inboxes are more real than ever.

Intermediate 5 min

BEC and FTF scams are leading to a steep rise in cyber insurance claims!

As per the recent Coalition 2025 Cyber Claims Report, business email compromise-based attacks (BEC) and fund transfer frauds (FTF) have led to a steep surge in.

Foundational 7 min

What is an executive phishing attack and how to prevent it?

Threat actors try different tactics to intercept and steal data, which is further exploited for financial gain. One such tactic is an executive phishing attack.

Advanced 5 min

The healthcare industry is the most sought-after by cybercriminals

The healthcare industry depends a lot on technology - whether it’s online appointments, digital health records, or connected medical devices.

Intermediate 5 min

Fixing typical SPF errors

SPF prevents spoofing by ensuring that only trusted sources can send emails using your domain. But for it to work well, the SPF record must be error-free.

Fix your SPF record, free

Give us a test drive for 30 days at no cost. Fix your broken SPF in less than 60 seconds!