checkdmarc

A Python module, command line utility, and web application for validating SPF and DMARC DNS records.

Features

• API, CLI, and web interfaces
• Can test multiple domains at once
• CLI output in JSON or CSV format
• DNSSEC validation
• SPF
  • Record validation
  • Counting of DNS lookups and void lookups
  • Counting of lookups per include
• DMARC
  • Validation and parsing of DMARC records
  • Shows warnings when the DMARC record is made ineffective by pct or sp values
  • Checks for authorization records on reporting email addresses
• BIMI
  • Validation of the mark format and certificate
  • Parsing of the mark certificate
• MX records
  • Preference
  • IPv4 and IPv6 addresses
  • Checks for STARTTLS
  • Use of DNSSEC/TLSA/DANE to pin certificates
• MTA-STS
• SMTP TLS reporting
  • Record and policy parsing and validation
• SOA record parsing
• Nameserver listing