Network tools
17 toolsDNS, whois, SSL, headers and other lookups.
DNS Lookup
Look up every DNS record type for a domain in one query: A, AAAA, MX, TXT, NS, CNAME, SOA...
Hostname to IP
Resolve a hostname to every IPv4 and IPv6 address it points to, and see which CDN or host...
IP to Hostname
Run a reverse DNS lookup on any public IP address and see the PTR records it resolves to.
Whois Lookup
Look up whois data for any domain: registrar, creation and expiry dates, status codes and...
SSL Checker
Check a TLS certificate: issuer, validity dates, days until expiry, covered host names,...
HTTP Header Checker
Fetch any URL and read every HTTP response header, with security headers, caching and...
HTTP Status Checker
Check the HTTP status code any URL returns, with the meaning explained and the full...
Website Status Checker
Check whether a website is up from outside your network, with status code, response time,...
Redirect Checker
Follow a URL through every redirect and see each hop with its status code, target and...
URL Unshortener
Expand a shortened link and see the full destination before you visit it, including every...
Compression Test
Check whether a URL is served compressed, which algorithm is used, and how many bytes...
Ping Test
Measure round trip time to any public host from our server, with four samples, best,...
Port Checker
Check whether specific ports are reachable on a host from outside your network.
SMTP Test
Connect to a mail server and read its greeting and advertised capabilities, including...
Page Source Viewer
Fetch the raw HTML a server returns for any URL, before JavaScript runs.
What Is My IP
See the public IP address your connection presents to websites, with reverse DNS and the...
IP Information
Look up any public IP address: registry data on the owning network, allocation range,...
When a domain misbehaves, the questions are always the same: where does it point, who runs it, is the certificate valid, which headers come back. These tools answer them in one click. Unlike everything else on this site they run from our server, because the question is about the internet, not about your data: each page says so plainly, and what you enter is used for the lookup and not stored.