Free tools
Quick IP, DNS, SSL and port checks. Each tool runs on demand, stores no personal data, and is rate-limited to prevent abuse.
Look up any public IP: ASN, network organization, range and reverse hostname, backed by real RDAP data.
Resolve the reverse hostname (PTR record) of any public IP in seconds.
Calculate network, broadcast, netmask and usable host range from an IPv4 CIDR notation.
Convert an IPv4 address to decimal, hexadecimal and binary instantly.
Check which common ports (web, mail, databases, admin) respond on an authorized domain or IP.
Measure latency, packet loss and availability of a host with four ICMP packets.
Shows the network hops to a destination to investigate slow routes or intermediate cuts.
Checks whether a domain publishes an IPv6 address (AAAA record).
Look up A, AAAA, MX, TXT, NS, CNAME or SOA records for any domain in real time.
Look up A, AAAA, MX, TXT, NS, CNAME or SOA records for any domain in real time.
Look up A, AAAA, MX, TXT, NS, CNAME or SOA records for any domain in real time.
Checks whether a domain has DNSSEC signed according to Google and Cloudflare resolvers.
Compares a DNS record's answer between Google and Cloudflare to see if a change has already propagated.
Technical summary of DNS, SSL, HTTP headers and mail for a domain in a single view.
Checks whether a domain publishes a valid SPF record to authorize outgoing mail servers.
Looks for a DKIM record published under the most common selectors of a domain.
Checks the DMARC policy published by a domain and how strict it is.
Checks a domain's mail servers (MX) and whether the primary one appears on public blacklists.
Connects to a domain's mail server and checks its banner and STARTTLS support, without sending mail.
Combined score of MX, SPF, DKIM, DMARC and STARTTLS for a mail domain.
Check the issuer, domain and expiration date of any domain's SSL/TLS certificate.
Verify whether an authorized domain has HSTS, CSP, X-Frame-Options and other key security headers enabled.
Verify whether an authorized domain has HSTS, CSP, X-Frame-Options and other key security headers enabled.
Detects which TLS versions a server accepts, including obsolete protocols like TLS 1.0 and 1.1.
Follows a URL's full redirect chain and detects loops or lost HTTPS.
Checks whether a site enforces HTTPS with HSTS, its duration, and whether it is on the browser preload list.
Check which common ports (web, mail, databases, admin) respond on an authorized domain or IP.
Checks whether an IP or domain appears on known public DNSBL blacklists.
Checks whether a domain appears on Spamhaus DBL, a public list associated with spam, phishing and malware.
Combines SPF, DMARC, HTTPS, domain age and brand-similarity signals into a risk level.
Detects common CMS, frameworks and providers from a site's headers and public HTML.