This is our short list of recommended networking resources: the tools, services, and references we actually use and trust. Where we suggest a paid product, a full buyer’s guide sits behind it. It explains the honest tradeoffs and shows you how to verify any claim with our free tools. Run the tool, read the output.
Your privacy & security stack
The services we trust to keep your traffic, identity, network, and inbox private and secure.
How to Choose a VPN
The seven criteria that actually matter when picking a VPN. Plus how to verify a provider’s claims yourself instead of trusting the marketing.
Read the guide →How to Choose a Secure Email Provider
The encryption, jurisdiction, and authentication that actually matter, plus vetted picks and how to test any provider’s records yourself.
Read the guide →Best Network Security Software
Our roundup of the firewall, endpoint, and network security software worth paying for. Real head-to-head comparisons, not spec-sheet marketing.
Read the guide →Checking a mail provider before you commit? Run its domain through our Email Auth Checker, MX Lookup, and MTA-STS Checker.
Run your site securely
Hosting and infrastructure picks for people who care about security, not just price.
Our free diagnostic tools
The tools other sites tell you to go run. No signup, no limits, right in your browser.
Browse the full set at the Network Tools hub, or jump straight to the most-used ones:
What Is My IP Address?
Instantly find your public IP with geolocation: city, region, country, and ISP.
Open tool →DNS Record Checker
Query A, AAAA, MX, TXT, CNAME, and NS records for any domain over DNS-over-HTTPS.
Open tool →DNS Health Checker
Audit a domain’s core records, email authentication, DNSSEC, and reverse DNS in a single pass.
Open tool →DNS Speed Test
Benchmark public DNS resolvers from your location to find the fastest one for you.
Open tool →Firefox DoH Canary Checker
Check whether this browser can reach Firefox’s DNS-over-HTTPS opt-out signal — the domain behind silent Pi-hole bypass.
Open tool →SSL Certificate Checker
Inspect any site’s SSL certificate: issuer, validity dates, and chain details.
Open tool →Blacklist Check
See whether an IP or domain appears on major email and spam blacklists.
Open tool →SPF Record Lookup
Check and parse a domain’s SPF record to confirm its email-sending policy.
Open tool →Subnet Calculator
Work out network ranges, masks, broadcast, and host counts from any CIDR block.
Open tool →See all tools
The complete set of free diagnostic and calculator tools in one place.
Open the hub →Reference & standards
The primary sources we cite. Bookmark these, not the blog summaries of them.
- RFC EditorThe actual protocol standards (TCP, DNS, HTTP, and more).
- NIST CSRCU.S. security standards and publications, including FIPS and SP 800 series.
- IANAThe authority for IP allocations, port numbers, and protocol parameters.
- OWASPWeb application security guidance and the Top 10 risk list.
- EFFDigital privacy and security advocacy and practical guides.
- MDN Web DocsThe reference for HTTP, web protocols, and browser behavior.
- Let’s EncryptFree, automated TLS certificates for the whole web.
Free tools worth learning
Third-party free and open-source tools the networking and home-lab crowd actually runs.
Several of these are compared head-to-head in our guide to the best free network monitoring tools for home labs.
- NmapThe essential free port scanner and network mapper.
- WiresharkThe standard free packet analyzer for deep traffic inspection.
- Uptime KumaSelf-hosted, free uptime and status-page monitoring.
- NetBoxOpen-source IP address management (IPAM) and infrastructure modeling.
- draw.io (diagrams.net)Free network and architecture diagramming in the browser.
- GNS3Free network simulator for labbing CCNA and beyond.