What Is My IP?
See the public IP address websites see, plus your browser, language, timezone and screen details.
Open tool →Network diagnostics, without the guesswork.
NetTools is a small, fast collection of browser-based utilities for checking how the internet sees you — and how the services you rely on look from the outside. No sign-up, no software to install, and no mystery: every tool explains what it measured and what the result actually means.
DNS Lookup
Query A, AAAA, CNAME, MX, NS, TXT and SOA records for any domain over encrypted DNS-over-HTTPS.
Open tool →SSL Checker
Inspect a site's TLS certificate: issuer, expiry date, subject alternative names, protocol and cipher.
Open tool →Port Checker
Test whether a TCP port on a host you own is reachable from the outside, and how fast it answers.
Open tool →Speed Test
Measure ping, download and upload throughput between your browser and this server.
Open tool →Subnet Calculator
Turn an IP address and CIDR prefix into network, broadcast, netmask and usable host range.
Open tool →JSON Formatter
Pretty-print, validate and minify JSON locally in your browser, with clear error locations.
Open tool →Password Generator
Create strong, random passwords with the length and character sets you choose.
Open tool →Base64 Encoder / Decoder
Encode text to Base64 or decode Base64 back to readable text, entirely on your device.
Open tool →Timestamp Converter
Convert Unix timestamps to human-readable dates, and dates back to timestamps, in any timezone.
Open tool →User Agent Parser
Break a user-agent string down into browser, engine, operating system and device type.
Open tool →Start with the basics
Not sure where to begin? Run the IP check first, then verify DNS and SSL for the site you are troubleshooting.
Start troubleshooting →What online network diagnostics can — and cannot — tell you
When something online misbehaves, the fault usually sits in one of a handful of places: your device, your local network, your internet provider, the DNS system that translates names into addresses, the TLS layer that secures the connection, or the server at the far end. Good diagnostics do not magically fix any of those. What they do is narrow the field, quickly and with evidence, so you stop guessing and start checking the right thing. That is the job of the tools on this page.
Start with identity. The IP checker shows the public address the outside world sees when you browse. That single fact explains a surprising number of mysteries: a streaming service that thinks you are in another country, an office firewall that will not let you in, or a login alert you do not recognise. If the address is not the one you expected, a VPN, a corporate proxy, carrier-grade NAT or a changed provider assignment is usually the reason.
Next comes naming. Every connection begins with DNS, and stale or misconfigured records are among the most common causes of “the site is down” reports that are really “the site moved and my resolver has not caught up.” A DNS lookup shows exactly which addresses, mail servers and verification records a domain publishes, together with the time-to-live values that control how long answers are cached. If a record was changed an hour ago and its TTL is a day, propagation — not breakage — is the likely story.
Then comes trust. The SSL checker opens a real TLS handshake with a server and reports the certificate it presents: who issued it, which names it covers, and how many days remain before it expires. Most certificate outages are not attacks; they are renewals that nobody noticed until browsers started warning every visitor away. Checking expiry dates before they lapse is one of the cheapest reliability habits a site owner can build.
Reachability is the fourth layer. A port check answers a deliberately narrow question: can a TCP connection be opened to this host and port from outside? An open result proves the path works end to end. A closed or filtered result points at a firewall, a NAT rule that was never written, or a service that is not listening — three very different fixes that a single test helps you tell apart.
Interpreting results responsibly
A diagnostic result is a measurement from one place, at one moment, over one path. Treat it that way. A port that is closed from here may be open from your office if the host only allows certain source addresses. A speed test measures the route between you and this server, not your provider's headline rate. An IP geolocation is an approximation maintained by third parties, not a GPS fix. Use these tools to form a hypothesis, then confirm it with a second test from a different network before you change anything important.
Responsible use matters just as much. Only scan, probe or test systems that you own or have explicit permission to test. Checking whether your own mail server accepts connections is routine maintenance; sweeping a stranger's address range is not, and in many jurisdictions it is unlawful. The tools here are intentionally modest — single hosts, single ports, public records — because that is what legitimate troubleshooting needs.
Your privacy while you test
Several tools here run entirely in your browser: the DNS lookup talks directly to an encrypted resolver, and the formatters, generators and calculators never send your input anywhere. The checks that must originate from our server — IP, SSL and port tests — are performed on demand, are rate-limited, and return their results to you without building a profile of what you tested. You can read the details on our privacy page. Sensible habit: avoid pasting secrets such as passwords, private keys or session tokens into any online tool, including ours.
Frequently asked questions
Are these tools free?
Yes. Every tool on NetTools is free to use, with no account and no download. Server-backed checks are rate-limited so the service stays fast for everyone.
Why do two tools sometimes disagree?
Because they measure from different places. Your browser, our server and a public resolver each see a different path through the internet, and caching means they may hold answers of different ages. Disagreement is itself useful diagnostic information.
Can I use these tools for work?
Yes, for systems you own or are authorised to test. Many people use the DNS, SSL and port checkers as a quick external sanity check after a change or during an incident.