ACME/Validationについて、ここに記述してください。 https://www.eff.org/ja/deeplinks/2018/02/technical-deep-dive-securing-automation-acme-dns-challenge-validation A Technical Deep Dive: Securing the Automation of ACME DNS Challenge Validation By Joona Hoikkala February 26, 2018 What's A Wildcard Certificate? How Does the DNS Challenge Work? [[opensslコマンド]]