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DNS
- DNS Lookup See the DNS records a domain publishes, with TTLs and an explanation of each record type.
- MX Lookup Find the mail servers that receive e-mail for a domain, in the order senders try them.
- DNS Propagation Checker Compare the same record across major public resolvers and the domain's authoritative name servers.
Domains & IP addresses
- WHOIS Lookup See a domain's registrar, registration and expiry dates, status codes and name servers, straight from the registry.
- IP WHOIS Lookup Find out which organisation an IP address range is registered to, and where to report abuse.
- Reverse IP Lookup Find the host name behind an IP address (PTR record) and check that it points back to the same address.
- What Is My IP Your public IP address as websites see it, with its reverse DNS host name.
E-mail authentication & delivery
- SPF Checker Validate a domain's SPF record, expand every include, and count DNS lookups against the limit of 10.
- DMARC Checker Find a domain's DMARC policy, check its syntax and see in plain language what receivers will do with failing mail.
- DKIM Lookup Check the DKIM public key published for a selector, including key type, size and flags.
- Blacklist Checker Check whether an IP address, or the servers behind a domain, appear on public DNS blocklists.
- Email Header Analyzer Paste a message's raw headers to see where it came from, how long each hop took and whether it passed authentication.
- MTA-STS & TLS-RPT Checker Check that sending servers are told to deliver your mail only over verified TLS, and that you receive TLS failure reports.
- BIMI Checker Check whether your brand logo can appear next to your e-mails in Gmail, Yahoo and Apple Mail.
Web & TLS
- SSL Certificate Checker Check a server's TLS certificate: whether it is trusted, matches the host name and how long until it expires.
- HTTP Header Checker See the response headers a web page returns and how its security headers are set up.
- Redirect Checker Follow a URL through every redirect and see each status code and destination.
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