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
A Record Lookup
IPv4 addresses for a domain
AAAA Record Lookup
IPv6 addresses for a domain
MX Lookup
Mail servers for a domain
NS Lookup
Authoritative name servers
TXT Lookup
TXT records, SPF, verification
CNAME Lookup
Canonical name (alias) records
SOA Lookup
Start of Authority record
SRV Lookup
Service location records
CAA Lookup
Which CAs may issue certificates
Reverse DNS (PTR)
IP address to hostname
DNSSEC Check
Is the domain signed and validated?
DNS Health Check
A full delegation & DNS report card
Email Deliverability
SPF Check
Validate your Sender Policy Framework record
DMARC Check
Inspect and grade your DMARC policy
DKIM Check
Find and validate your DKIM public key
Blacklist Check
Check an IP against email blocklists (DNSBLs)
SMTP Test
Connect to a mail server and check STARTTLS
MTA-STS Check
Enforced TLS policy for inbound mail
BIMI Check
Brand logo record for email
TLS-RPT Check
SMTP TLS reporting policy
Network & Web
Domain
Native macOS App
IP Intelligence Tool
Quick IP lookups and geolocation from your menu bar