A collection of useful online tools that can help diagnose DNS, email, networking, website, and security issues.
Introduction
Whether you’re troubleshooting a website, investigating an email delivery problem, validating DNS records, or checking network connectivity, the right tools can save a significant amount of time.
This article lists some of the most useful online resources for home users, IT professionals, website owners, and system administrators.
🌐 DNS & Email Tools
MXToolbox SuperTool
Best For
- DNS lookups
- Email diagnostics
- SPF/DKIM/DMARC validation
- Blacklist checking
- Domain investigations
Website
Useful Checks
✅ MX Records
✅ SPF Records
✅ DKIM Records
✅ DMARC Records
✅ DNS Lookups
✅ Blacklist Status
DNS Checker
Best For
Checking global DNS propagation.
Website
Useful Checks
✅ A Records
✅ MX Records
✅ TXT Records
✅ CNAME Records
✅ DNS Propagation
🌍 IP Address & Network Tools
What Is My IP
Best For
Identifying your public internet IP address.
Website
Useful Information
✅ Public IP Address
✅ ISP Information
✅ Approximate Geolocation
IPinfo
Best For
Investigating public IP addresses.
Website
Useful Information
✅ IP Ownership
✅ ASN Details
✅ Location Information
✅ Network Provider Information
Ping.eu
Best For
External network testing.
Website
Includes
✅ Ping
✅ Traceroute
✅ DNS Lookup
✅ WHOIS
✅ Port Checks
🔍 Website & DNS Investigation Tools
Whois Lookup
Best For
Checking domain ownership and registration information.
Website
Useful Information
✅ Domain Registrar
✅ Registration Dates
✅ Nameservers
✅ Domain Status
📧 Email Security Tools
DMARC Analyzer
Best For
Checking email authentication records.
Website
Useful Checks
✅ SPF Validation
✅ DMARC Validation
✅ Email Security Configuration
🔒 Security Tools
Have I Been Pwned
Best For
Checking whether an email address has appeared in known data breaches.
Website
Useful Information
✅ Breach Exposure
✅ Password Breach Checks
✅ Security Awareness
⚡ Website Performance Tools
PageSpeed Insights
Best For
Analysing website performance.
Website
Useful Information
✅ Mobile Performance
✅ Desktop Performance
✅ Core Web Vitals
✅ Performance Recommendations
Microsoft Learn
Best For
Official Microsoft technical documentation.
Website
Useful Information
✅ Microsoft 365
✅ Windows
✅ Azure
✅ PowerShell
🛠️ Everyday Network Utilities
| Tool | Use Case |
|---|---|
| MXToolbox | DNS and email diagnostics |
| DNS Checker | DNS propagation |
| WhatIsMyIP | Public IP lookup |
| Ping.eu | External ping and traceroute |
| VirusTotal | Security investigations |
| Have I Been Pwned | Breach checking |
| PageSpeed Insights | Website performance |
| GTmetrix | Website optimisation |
| Remote Connectivity Analyzer | Microsoft 365 troubleshooting |