MXToolbox

Comprehensive suite of network diagnostic and email infrastructure tools. MXToolbox is the industry standard for troubleshooting DNS, email deliverability, and network issues.

Features

Email Diagnostics

• MX Lookup: Check mail server records and configuration
• Email Health: Comprehensive email server health checks
• Blacklist Check: Verify if your IP/domain is blacklisted
• SPF Record Check: Validate SPF records for email authentication
• DKIM Lookup: Check DomainKeys Identified Mail configuration
• DMARC Lookup: Validate DMARC policies
• Email Header Analyzer: Trace email routing and identify delivery issues

DNS Tools

• DNS Lookup: Query any DNS record type (A, AAAA, CNAME, TXT, etc.)
• DNS Propagation: Check DNS changes globally
• Reverse DNS: PTR record verification
• DNS Health: Comprehensive DNS configuration analysis
• DNSSEC Validation: Verify DNSSEC implementation
• DNS Traversal: Trace complete DNS query path

Network Diagnostics

• Ping: ICMP echo test to verify connectivity
• Traceroute: Trace network path to destination
• Port Check: Test if specific ports are open
• HTTP Headers: Analyze HTTP response headers
• SSL/TLS Check: Verify certificate validity and configuration
• WHOIS Lookup: Domain registration information

Monitoring (Paid)

• 24/7 Monitoring: Continuous monitoring of mail servers and DNS
• Alerts: Instant notifications for issues
• Blacklist Monitoring: Alert when listed on blacklists
• Performance Tracking: Historical data and trends
• Uptime Monitoring: Track service availability

Common Use Cases

Email Deliverability

• Troubleshoot why emails aren't being delivered
• Verify email authentication (SPF, DKIM, DMARC)
• Check if sender IP is blacklisted
• Diagnose bounce messages
• Validate mail server configuration

DNS Troubleshooting

• Verify DNS records are correct
• Check DNS propagation after changes
• Troubleshoot website accessibility issues
• Validate SSL certificate configuration
• Debug subdomain routing problems

Server Configuration

• Verify MX records for mail servers
• Check reverse DNS for servers
• Validate SSL/TLS certificates
• Test port accessibility
• Diagnose network connectivity

Email Authentication Setup

SPF (Sender Policy Framework)

v=spf1 include:_spf.google.com ~all

Defines which servers can send email for your domain.

DKIM (DomainKeys Identified Mail)

Cryptographic signature proving email authenticity.

DMARC (Domain-based Message Authentication)

v=DMARC1; p=quarantine; rua=mailto:[email protected]

Policy for handling authentication failures.

Pricing

• Free Tools: Basic lookups and diagnostic tools
• Free Monitor: 1 monitor with limited features
• Plus: $139/month - 25 monitors, advanced features
• Pro: $299/month - 100 monitors, API access
• Enterprise: Custom pricing - Unlimited monitors

Best For

• Email Administrators: Troubleshooting deliverability issues
• DevOps Engineers: DNS and network diagnostics
• System Administrators: Server configuration verification
• Security Teams: Monitoring for blacklists and vulnerabilities
• Developers: Verifying email infrastructure setup
• IT Support: Quick diagnostic tools

Key Tools Quick Reference

Tool	Purpose	Common Use
MX Lookup	Find mail servers	Setup email
Blacklist Check	Check reputation	Email deliverability
SPF Lookup	Verify sender policy	Authentication
DNS Lookup	Query DNS records	Troubleshooting
Port Scanner	Check open ports	Server config
SSL Check	Verify certificates	Security validation

Pro Tips

• Always check blacklists when emails aren't being delivered
• Use the Super Tool for comprehensive diagnostics
• Verify SPF, DKIM, and DMARC before launching email campaigns
• Check DNS propagation after making DNS changes
• Save common lookups as bookmarks for quick access
• Use monitoring for production email servers

MXToolbox is an essential resource for anyone managing email infrastructure, DNS, or network services. The free tools alone make it invaluable for troubleshooting.