Network Diagnostics Toolkit

Free browser-based tools for network diagnostics, IP intelligence and DNS inspection. No installs, no accounts – just results. Built for engineers, sysadmins and IT professionals.

Your Current IP AddressWhat is this?
IPv4detecting…
IPv6detecting…
ISP:
Version:
Location:
Timezone:
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Ping Test

A ping test measures the round-trip time (RTT) between your browser and a target host. This browser-based tool uses fetch() timing to approximate latency – useful for quick connectivity checks and identifying high-latency connections on 4G/5G or satellite links. Open Ping Test

IP Lookup Tool

Enter any IPv4 or IPv6 address to retrieve geolocation, ISP, ASN (Autonomous System Number), organisation, country, region, city and timezone data. Useful for verifying VPN exit nodes, tracing traffic sources, or auditing server configurations. Open IP Lookup

DNS Lookup

Query DNS records for any domain – including A, AAAA, MX, TXT, CNAME, NS and PTR records – using Cloudflare’s DNS over HTTPS (DoH) resolver. Useful for verifying DNS propagation, diagnosing mail delivery issues, or checking SPF/DKIM records. Open DNS Lookup

Port Checker

Check whether a specific TCP port is open or closed on a remote host. Useful for diagnosing firewall rules, verifying that services are listening on expected ports, or confirming remote access is correctly configured. Open Port Checker

Traceroute

Traceroute maps the network path between your location and a destination, showing each hop and the latency at each point. True browser-based traceroute is not possible due to ICMP/TTL restrictions in browser sandboxes. Use your OS command line or the PingReboot desktop tool for a full traceroute. View Options

Subnet Calculator

Enter a CIDR notation address (e.g. 192.168.1.0/24) to calculate the network address, subnet mask, wildcard mask, broadcast address, first and last usable host, and total number of hosts. Essential for IP planning and network segmentation. Open Subnet Calculator

Reverse DNS Lookup

Reverse DNS (rDNS) resolves an IP address back to its associated hostname via the PTR record. Commonly used to verify mail server configurations, identify device owners, or validate that a server’s forward and reverse DNS records match. Open Reverse DNS

Speed Test

Test your internet connection’s download speed, upload speed and latency using real file transfers via Cloudflare edge endpoints. Useful for benchmarking 4G/5G routers, SIM cards and fixed-line connections. Open Speed Test

Frequently Asked Questions

What is my IP address?
Your IP address is shown automatically at the top of this page. It is assigned by your ISP or mobile network operator and identifies your device on the internet. It can be a shared address if you are behind NAT (e.g. on a 4G connection) or a dedicated address on a business line.
How do I check if a port is open?
Use the Port Checker tool above. Enter the host and port number. Common ports include 22 (SSH), 80 (HTTP), 443 (HTTPS), 3389 (RDP) and 1194 (OpenVPN).
What is a DNS lookup?
A DNS lookup queries the Domain Name System to retrieve records for a domain. Common types include A (IPv4), AAAA (IPv6), MX (mail), TXT (SPF/DKIM), CNAME (alias) and NS (nameserver).
How do I ping a website?
The Ping Test uses browser fetch() timing to approximate latency. For a true ICMP ping: on Windows type “ping hostname”, on macOS or Linux type “ping -c 4 hostname”.
What is a subnet calculator used for?
A subnet calculator divides an IP address range into smaller segments. Enter a CIDR block such as 192.168.1.0/24 to find the usable IP range, broadcast address, subnet mask and total host count.
What is reverse DNS and why does it matter?
Reverse DNS maps an IP address back to a hostname via a PTR record. Mail servers check rDNS to verify sending IPs. Missing or mismatched rDNS can cause email to be marked as spam.

🔌 Ping Test

Measures approximate round-trip latency using browser fetch() timing. Runs 6 requests and reports min/avg/max. This is a browser approximation – TCP handshake overhead is included. Use command-line ping for raw ICMP results.

Enter a host and click Run Ping.
Browser-based ping measures HTTP/S fetch latency, not raw ICMP. Results may be higher than command-line ping due to TLS handshake overhead on the first request.

🔍 IP Lookup

Enter any IPv4 or IPv6 address to retrieve geolocation, ISP, ASN and organisation data via ipapi.co.

Enter an IP address to look up.

🌐 DNS Lookup

Query DNS records for any domain via Cloudflare’s DNS over HTTPS resolver (1.1.1.1).

Enter a domain and click Query.

🔒 Port Checker

Check whether a TCP port is open on a remote host. Uses HTTP/S connection timing to detect reachability from this browser.

Enter a host and port to check.
Port checking from a browser is limited by CORS and browser security policy. Ports 80 and 443 give the most reliable results. For full port scanning, use nmap on the command line.

🕐 Traceroute

True traceroute requires raw ICMP socket control not available in browser sandboxes. We will not generate fabricated hop data.

🕐
Use Your OS Command Line
Windows: tracert hostnameLinux / macOS: traceroute hostname
Learn About PingReboot

📊 Subnet Calculator

Enter a CIDR notation address to calculate all subnet parameters. IPv4 only.

Enter a CIDR block to calculate.

↻ Reverse DNS Lookup

Resolve an IP address back to its associated hostname via PTR record using Cloudflare’s DoH resolver.

Enter an IP address to resolve its hostname.

⚡ Speed Test

Tests download speed via a 10MB file transfer and upload via POST request to Cloudflare edge. Results are approximate and affected by browser overhead.

Download
Mbps
Upload
Mbps
Click Start Test to begin.
Speed test uses a 10MB download from Cloudflare edge and a 1MB upload POST. For a dedicated mobile broadband speed test, visit fast.com.