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, there is a full buyer’s guide behind it that explains the honest tradeoffs and shows you how to verify any provider’s claims with our free tools. Run the tool, read the output.
Your privacy & security stack
The services we trust to keep your traffic, identity, and inbox private.
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 full buyer’s guide is in the works. In the meantime, you can check any domain’s email security yourself with our free tools:
Check email security now:
Run your site securely
Hosting and infrastructure picks for people who care about security, not just price.
How to Choose Web Hosting
The full security-first hosting guide is in the works. In the meantime, you can vet any host yourself with our free tools:
Vet any host now:
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 Speed Test
Benchmark public DNS resolvers from your location to find the fastest one for you.
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.
- 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.ioFree network and architecture diagramming in the browser.
- GNS3Free network simulator for labbing CCNA and beyond.