Network & website tools

About these tools

All 24 tools in this section are free, work in your browser on any device, and need no sign-up.

• What is my IP? (IP address lookup): See your public IP address with its country, city and internet provider, or look up any IP or domain.
• DNS lookup: Find a domain's A, AAAA, MX, TXT, CNAME, NS, SOA and CAA records, with SPF and DMARC explained.
• WHOIS lookup: Domain registration details: registrar, creation and expiry dates, name servers and status.
• Is it down? Website status checker: Check whether a website is online for everyone or just you, and what's wrong if it isn't.
• Website response time: Measure how fast a website answers: DNS, connection, SSL, server wait and download time.
• HTTP headers checker: See every response header of a page and get a security headers grade with fixes.
• Redirect checker: Follow a link through every redirect (301, 302, meta refresh) to see where it really goes.
• SSL certificate checker: Check a website's SSL/TLS certificate: expiry date, issuer, covered domains and chain problems.
• IP subnet calculator: Network, broadcast, usable host range and mask for any IPv4 or IPv6 CIDR, and split it into subnets.
• Port number lookup: What runs on a port: search common TCP/UDP port numbers and services.
• MAC address lookup: Find the manufacturer of a network device from its MAC address (official IEEE list).
• User agent parser: Find out the browser, operating system and device behind any user agent string.
• My browser info: Everything your browser shares: version, screen, language, time zone, cookies, graphics and more.
• Robots.txt tester: Fetch or paste a robots.txt and test whether Googlebot and other crawlers may visit a URL.
• Sitemap XML validator: Check an XML sitemap for errors: required tags, URLs, dates, size limits and duplicates.
• HTTP status codes: Every HTTP status code explained in plain words, with what to do about it (404, 500, 503…).
• SPF and DMARC record generator: Write the SPF, DKIM and DMARC DNS records that stop your email going to spam.
• Email blacklist checker: Check whether a mail server's IP is on common spam blocklists.
• Website technology checker: See which CMS, framework, server, analytics and CDN a website uses.
• Wake-on-LAN magic packet generator: The magic packet and the commands to wake a computer on your own network, for Linux, macOS and Windows.
• ASN and IP prefix lookup: Find the network (ASN) that owns an IP address, domain or AS number, and the prefixes it announces.
• DNS propagation checker: Check what five big public DNS resolvers answer for a domain, and whether they agree.
• Internet speed test: Measure your download speed, upload speed, latency and jitter to this site.
• SPF, DKIM and DMARC record checker: Check a domain's SPF, DKIM and DMARC records for mistakes, with the 10-lookup limit and what to fix.