Test tool havedane.net and NCSC-NL factsheet on DANE

1. Check this new tool for testing if your mail server checks DANE when sending email: https://havedane.net

2. Recently the Dutch NCSC published a factsheet "Secure the connections of mail servers" with regard to DANE and STARTTLS. See: https://www.ncsc.nl/english/current-topics/factsheets/factsheet-secure-the-c...