Email Authentication Tools & Resources

A curated list of the best tools for email authentication, DMARC monitoring, SPF/DKIM validation, and deliverability testing. Use these tools alongside MailSentinel to ensure complete email security.

Free DNS & Authentication Tools

MXToolbox

URL: https://mxtoolbox.com

Features:

SPF record checker
DKIM validator
DMARC lookup
MX record checker
Blacklist checker
DNS lookup

Best For:

Quick DNS record checks
Troubleshooting authentication issues
Blacklist monitoring
General email diagnostics

Limitations:

Free tier has rate limits
No historical tracking
Manual checks only

SPF Record Checker

URL: https://mxtoolbox.com/spf.aspx

Features:

SPF record validation
DNS lookup counting
Include tree visualization
Syntax validation

Best For:

Validating SPF records
Checking lookup count
Finding syntax errors

DKIM Validator

URL: https://mxtoolbox.com/dkim.aspx

Features:

DKIM record lookup
Key validation
Selector discovery
Public key verification

Best For:

Checking DKIM setup
Validating keys
Finding selectors

DMARC Analyzer

URL: https://www.dmarcanalyzer.com

Features:

DMARC record lookup
Policy validation
Report address checking
Syntax validation

Best For:

Validating DMARC records
Checking policy syntax
Verifying report addresses

Email Deliverability Testing Tools

Mail-Tester

URL: https://www.mail-tester.com

Features:

Spam score (0-10)
Authentication checks
Blacklist checking
Content analysis
Header analysis

Best For:

Testing individual emails
Getting spam score
Identifying deliverability issues
Content optimization

How to Use:

Send test email to provided address
Get instant spam score
Review detailed analysis
Fix identified issues

GlockApps

URL: https://glockapps.com

Features:

Multi-ISP inbox placement testing
Spam folder testing
Authentication checks
Content scoring
Historical tracking

Best For:

Comprehensive deliverability testing
Multi-provider testing
Campaign validation
Content optimization

Pricing:

Personal: $59/month
Team: $99/month
Agency: $249/month

Litmus

URL: https://www.litmus.com

Features:

Email preview testing
Spam testing
Authentication checks
Rendering tests
Analytics

Best For:

Email design testing
Rendering across clients
Spam filter testing
Campaign optimization

Pricing:

Starts at $99/month

Provider-Specific Tools

Google Postmaster Tools

URL: https://postmaster.google.com

Features:

Spam rate monitoring
IP reputation tracking
Domain reputation
Delivery errors
Feedback loop data

Best For:

Gmail deliverability
Spam rate monitoring
Reputation tracking
Gmail-specific insights

Requirements:

Domain verification required
DKIM signing required
Historical data available

Microsoft SNDS

URL: https://sendersupport.olc.protection.outlook.com/snds/

Features:

IP reputation scores
Complaint rates
Volume data
Filtering status
Historical trends

Best For:

Outlook/Hotmail deliverability
IP reputation monitoring
Complaint rate tracking
Microsoft-specific insights

Requirements:

IP registration required
DKIM signing recommended
Historical data available

Yahoo Sender Hub

URL: https://senders.yahooinc.com

Features:

Best practices guide
Requirements documentation
Complaint feedback loop
Deliverability resources

Best For:

Yahoo deliverability
Requirements compliance
Best practices
Educational resources

DMARC Monitoring Tools

MailSentinel

URL: https://mailsentinel.io

Features:

DMARC report parsing
SPF/DKIM monitoring
Real-time alerts
Source identification
Historical analysis
Team collaboration

Best For:

Comprehensive DMARC monitoring
Real-time alerting
Team collaboration
Cost-effective solution

Pricing:

Starter: $14/month
Professional: $49/month
Enterprise: Custom

Dmarcian

URL: https://dmarcian.com

Features:

DMARC monitoring
Report analysis
Historical data
Team features

Best For:

Established DMARC monitoring
Enterprise features
Comprehensive reporting

Pricing:

Starts at $8/month
Enterprise: Custom

PowerDMARC

URL: https://powerdmarc.com

Features:

DMARC monitoring
BIMI support
Threat intelligence
MTA-STS hosting

Best For:

Comprehensive email security
BIMI implementation
Threat detection

Pricing:

Starts at $8/month
Enterprise: Custom

SPF Flattening Tools

SPF Flattening Services

Purpose:

Reduce DNS lookups
Convert includes to IP ranges
Optimize SPF records

Providers:

Postmark SPF Flattening
SendGrid SPF Flattening
Custom solutions

Best For:

Complex SPF records
Approaching lookup limit
Performance optimization

Email Header Analysis Tools

Message Header Analyzer

URL: https://mha.azurewebsites.net

Features:

Header parsing
Authentication analysis
Path visualization
Timestamp analysis

Best For:

Understanding email headers
Troubleshooting delivery
Authentication verification

Gmail Message Header Tool

URL: Built into Gmail

Features:

View full headers
Authentication results
Delivery path
Timestamps

How to Use:

Open email in Gmail
Click three dots → Show original
Review authentication headers

Blacklist Checking Tools

MXToolbox Blacklist Check

URL: https://mxtoolbox.com/blacklists.aspx

Features:

Check 100+ blacklists
IP and domain checking
Historical data
Removal guidance

Best For:

Quick blacklist checks
IP reputation monitoring
Troubleshooting blocks

MultiRBL

URL: https://multirbl.valli.org

Features:

Multiple blacklist checks
IP and domain checking
Detailed results
Historical data

Best For:

Comprehensive blacklist checking
Detailed analysis
Historical tracking

DNS Tools

DNS Checker

URL: https://dnschecker.org

Features:

Global DNS propagation
Record lookup
Propagation tracking
Multiple record types

Best For:

Checking DNS propagation
Global DNS verification
Record validation

Dig (Command Line)

Features:

DNS record lookup
Direct DNS queries
Multiple record types
Detailed results

Best For:

Advanced users
Scripting
Direct DNS queries
Troubleshooting

Usage:

# Check SPF
dig TXT example.com
 
# Check DMARC
dig TXT _dmarc.example.com
 
# Check DKIM
dig TXT default._domainkey.example.com

Email Authentication Validators

SPF Validator

URL: https://www.spf-record.com/spf-lookup

Features:

SPF record validation
Lookup counting
Include resolution
Syntax checking

Best For:

SPF record validation
Lookup optimization
Syntax verification

DKIM Checker

URL: https://www.dmarcanalyzer.com/dkim-check/

Features:

DKIM record lookup
Key validation
Selector discovery
Signature verification

Best For:

DKIM setup validation
Key verification
Selector finding

Reporting & Analytics Tools

Google Analytics

URL: https://analytics.google.com

Features:

Email campaign tracking
Click tracking
Conversion tracking
Engagement metrics

Best For:

Email campaign analytics
ROI measurement
Engagement tracking

Email Service Provider Analytics

Features:

Delivery rates
Open rates
Click rates
Bounce tracking
Engagement metrics

Best For:

Campaign performance
Deliverability tracking
Engagement analysis

Security & Compliance Tools

SSL Labs

URL: https://www.ssllabs.com/ssltest/

Features:

SSL/TLS testing
Certificate validation
Security grading
Configuration analysis

Best For:

Email server security
TLS configuration
Certificate validation

Security Headers

URL: https://securityheaders.com

Features:

Security header analysis
Configuration grading
Best practices
Recommendations

Best For:

Email server security
Header configuration
Security hardening

Educational Resources

DMARC.org

URL: https://dmarc.org

Features:

DMARC specification
Implementation guides
Best practices
Educational content

Best For:

Learning DMARC
Implementation guidance
Best practices

M3AAWG

URL: https://www.m3aawg.org

Features:

Email best practices
Industry standards
Research papers
Educational resources

Best For:

Industry best practices
Research and standards
Educational content

Tool Comparison Matrix

Tool	Type	Cost	Best For
MXToolbox	DNS/Auth	Free	Quick checks
Mail-Tester	Deliverability	Free	Spam scoring
MailSentinel	DMARC	$14-49/mo	DMARC monitoring
Google Postmaster	Gmail	Free	Gmail insights
Microsoft SNDS	Outlook	Free	Outlook insights
GlockApps	Testing	$59+/mo	Multi-ISP testing
Dmarcian	DMARC	$8+/mo	DMARC monitoring

Recommended Tool Stack

For Small Businesses

MailSentinel - DMARC monitoring ($14/month)
MXToolbox - Free DNS checks
Mail-Tester - Free spam testing
Google Postmaster - Gmail insights

Total Cost: $14/month

For Medium Businesses

MailSentinel - DMARC monitoring ($49/month)
GlockApps - Deliverability testing ($59/month)
MXToolbox - DNS checks
Provider tools - Google/Microsoft/Yahoo

Total Cost: $108/month

For Enterprises

MailSentinel - DMARC monitoring (Enterprise)
GlockApps - Comprehensive testing ($249/month)
Litmus - Email testing ($99+/month)
All provider tools - Complete visibility

Total Cost: Custom pricing

Getting Started

Set Up MailSentinel - Start DMARC monitoring
Use Free Tools - MXToolbox, Mail-Tester for validation
Register Provider Tools - Google Postmaster, Microsoft SNDS
Test Regularly - Use testing tools before campaigns
Monitor Continuously - Use MailSentinel for ongoing monitoring

Additional Resources

DMARC Setup Guide - Complete configuration
SPF Configuration - SPF setup
DKIM Configuration - DKIM setup
Email Delivery Troubleshooting - Fix issues