Brief list of various self-hosted or third-party tools I utilize.

Adminer – PHP-based database administration – Convert column data to comma-delaminated – Round-trip email delivery test

SPFToolbox – DNS query

File Share – Self-hosted file sharing

Email Security Validation – DKIM, SPF, Spam Testing – DomainKeys, DKIM, and SPF validity, and SpamAssassin score in one place – Basic SPF, DKIM, and SpamAssassin tests

NIST Email Authentication Tester – Sender and receiver tests