Choose the right check

Checked against v1.241.1 on 2026-11-02 · Source reviewed

Before you start

Have permission to inspect your target. Use a hostname without a URL path for DNS and TLS checks. Examples use fictional domains and documentation addresses; replace them with approved inputs.

Choose a task

• Find a published record: use DNS Lookup.
• Compare answers across resolvers: use DNS Propagation.
• Investigate a certificate warning: use SSL Check / TLS & HTTPS Diagnostics.
• Follow an HTTP redirect: use Redirect Tester.
• Review registration information: use WHOIS Lookup. Registry data can be redacted or unavailable.
• Find a hostname associated with an IP: request a PTR record in DNS Lookup. Reverse IP discovery is a different question: it looks for domains associated with an address and may be incomplete.
• Plan a cutover: review the launch checklist before making changes.

Read the result in context

Record the time, exact target, options and resolver or endpoint used. A timeout means the check did not establish an answer. It does not prove absence or failure for every visitor.

Access and saved work

Some tools require membership or an enabled feature. A guide does not grant access. Opening help runs no check. Submitting a tool may contact the target or its DNS servers; review its options first.

Verification scope: Current form labels, registry and source reviewed; live provider, mailbox, saved-work lifecycle and host acceptance remain separate.