Network Diagnostic Tools

DNS, email deliverability, web security and connectivity checks — instant, free, no signup.

DNS & Records

DNS Lookup

Every DNS record for any domain

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A Record Lookup

IPv4 addresses for a domain

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AAAA Record Lookup

IPv6 addresses for a domain

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MX Lookup

Mail servers for a domain

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NS Lookup

Authoritative name servers

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TXT Lookup

TXT records, SPF, verification

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CNAME Lookup

Canonical name (alias) records

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SOA Lookup

Start of Authority record

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SRV Lookup

Service location records

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CAA Lookup

Which CAs may issue certificates

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Reverse DNS (PTR)

IP address to hostname

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DNSSEC Check

Is the domain signed and validated?

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Email Deliverability

SPF Check

Validate your Sender Policy Framework record

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DMARC Check

Inspect and grade your DMARC policy

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DKIM Check

Find and validate your DKIM public key

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Blacklist Check

Check an IP against email blocklists (DNSBLs)

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SMTP Test

Connect to a mail server and check STARTTLS

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MTA-STS Check

Enforced TLS policy for inbound mail

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BIMI Check

Brand logo record for email

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TLS-RPT Check

SMTP TLS reporting policy

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Network & Web

SSL Certificate Check

Inspect a site's TLS certificate and expiry

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HTTP Header Check

Inspect response headers, redirects and security

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Ping (TCP)

Reachability and latency over TCP

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Port Check

Which common ports are open

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Domain

WHOIS Lookup

Registration data for domains, IPs and ASNs

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Native macOS App

IP Intelligence Tool

Quick IP lookups and geolocation from your menu bar

Download for macOS→