Free Network Tools
Calculate subnets, build DNS records, parse URLs, inspect HTTP headers, convert IP addresses, and look up MIME types. Every tool is free, requires no signup, and runs in your browser.
Why Use Online Network Tools?
Network administration, web development, and DevOps all require frequent lookups and calculations involving IP addresses, DNS records, HTTP headers, and URL structures. Having these tools available instantly in your browser eliminates context-switching to terminal commands or desktop applications. Whether you are planning a network migration, debugging API calls, or configuring a web server, these tools accelerate your workflow.
Calculate Subnets and IP Ranges
The Subnet Calculator takes any IPv4 address with a CIDR prefix and shows the network address, broadcast address, usable host range, subnet mask, and wildcard mask. It can split networks into smaller subnets and supports variable-length subnet masking (VLSM). The IP Address Converter converts between dotted-decimal, binary, hexadecimal, and integer representations of IPv4 addresses.
Build and Validate DNS Records
The DNS Record Builder generates properly formatted DNS records for all common types including A, AAAA, CNAME, MX, TXT, NS, SRV, and CAA. It produces output in BIND zone file format that you can paste directly into your DNS provider. The DNS over HTTPS Lookup queries public DNS resolvers to check record propagation and verify your configurations.
HTTP Reference and Debugging
The HTTP Status Codes tool provides a comprehensive searchable reference for all HTTP status codes with descriptions, common causes, and troubleshooting tips. The HTTP Header Inspector parses raw HTTP headers to identify security headers, caching directives, and potential issues. The HTTP Methods Reference documents all HTTP methods with their semantics, idempotency, and safe-method properties.
Parse URLs and User Agents
The URL Parser breaks any URL into its components - protocol, host, port, path, query parameters, and fragment - and decodes percent-encoded characters. The User Agent Parser identifies the browser, engine, operating system, and device from a user agent string, useful for debugging browser-specific issues and analyzing access logs.
MIME Types and File Extensions
The MIME Type Lookup maps between file extensions and their Content-Type values. Enter an extension to get the MIME type, or enter a MIME type to find which extensions use it. This is essential when configuring web server headers, building file upload validators, or debugging Content-Type mismatches.
Network Address Generation
The MAC Address Generator creates valid MAC addresses with configurable OUI prefixes and formatting. The Random Port Generator generates random TCP/UDP port numbers in configurable ranges for development and testing. The IPv6 ULA Generator creates unique local addresses conforming to RFC 4193 for private IPv6 networks.
Frequently Asked Questions
How do I calculate subnets from a CIDR block?
Enter an IP address with a CIDR prefix (like 192.168.1.0/24) into the Subnet Calculator. It will show you the network address, broadcast address, first and last usable host, subnet mask in dotted-decimal notation, wildcard mask, total number of hosts, and usable host count. You can also split a network into smaller subnets or find which subnet an IP belongs to.
What DNS records can I generate?
The DNS Record Builder generates A, AAAA, CNAME, MX, TXT, NS, SRV, PTR, CAA, and SPF records in BIND zone file format. It includes helpers for common configurations like email setup (MX + SPF + DKIM), website hosting (A + CNAME + www), and SSL certificate validation (CAA + TXT).
What is a MIME type?
A MIME type (Multipurpose Internet Mail Extensions) is a standard identifier for the format of a file sent over the internet. It consists of a type and subtype, like text/html, application/json, or image/png. Web servers use MIME types in the Content-Type header to tell browsers how to handle the response. The MIME Type Lookup tool maps between file extensions and their MIME types in both directions.
How does the URL parser work?
The URL Parser breaks any URL into its components: protocol (scheme), host, port, path, query parameters, fragment (hash), and authentication credentials. It also decodes percent-encoded characters and parses query strings into individual key-value pairs. This is useful for debugging API endpoints, redirect chains, and OAuth callback URLs.
Are these network tools safe to use?
Yes. Most tools run entirely in your browser using JavaScript with no network requests. The DNS over HTTPS Lookup tool does make external requests to public DNS resolvers (Cloudflare or Google) to perform lookups, but only sends the domain name you enter - no other data. All other tools process your input locally.