Discovery Tools
Use discovery tools when you are mapping an environment, finding related services, or gathering clues before a deeper DNS or email investigation.
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Start With The Right Tool
Find Related Hostnames
Start here when you need to enumerate likely subdomains or understand the wider hostname footprint of a domain.
Identify Hosted Services
Use DNS patterns and certificate clues to infer what platforms or providers are probably in use.
Look For DKIM Selectors
If you are validating mail setup and do not know the selector yet, start with a selector-focused discovery path.
Featured Tools
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Discovery
Subdomain Finder
Search certificate transparency data for related hostnames.
Hosted Service Fingerprint Finder
Identify likely hosted platforms and services from DNS clues.
CNAME Discovery
Discover CNAME records in use and identify likely linked services.
Certificate SAN Explorer
Fetch a TLS certificate and list its SAN hostnames.
DKIM Selector Finder
Try common selectors and discover likely DKIM records.
Featured Articles
What Is DNS TTL? Time to Live Explained
Learn what DNS TTL means, how DNS caching works, why TTL affects propagation and reliability, and how to choose the right TTL before a DNS change.
How to Fix SPF Softfail
A practical guide to fixing SPF softfail, including how to identify the sending domain, review the SPF policy, authorise senders, and tighten enforcement safely.
How to Check an MX Record
A practical guide to checking an MX record, reading priorities and targets, and confirming whether mail is routed to the provider you expect.
How to Fix DKIM Failures
A practical guide to fixing DKIM failures, including wrong selectors, missing records, bad key publication, and signing problems in email platforms.
How to Fix DMARC Failures
A practical guide to fixing DMARC failures, including SPF and DKIM alignment issues, missing records, third-party senders, and enforcement problems.
How to Fix MX Record Problems
A practical guide to fixing MX record problems, including wrong targets, bad priorities, mixed providers, and incomplete mail migrations.