checkdmarc is a Python module and command line utility for validating SPF and
DMARC DNS records.

Features:
- API and CLI
- Can test multiple domains at once
- CLI output in JSON or CSV format
- Parses and validates MX, SPF, and DMARC records
- Checks for DNSSEC deployment
- Lists name servers
- Checks for STARTTLS and TLS support on each mail server