DKIM 조회 DKIM: https://mxtoolbox.com/SuperTool.aspx?action=dkim:1564362555.thundermail._domainkey.thundermail.co.kr DKIM: https://toolbox.googleapps.com/apps/dig/#TXT/1564362555.thundermail._domainkey.thundermail.co.kr DMARC 조회 DMARC: https://mxtoolbox.com/SuperTool.aspx?action=dmarc:_dmarc.thundermail.co.kr DMARC: https://toolbox.googleapps.com/apps/dig/#TXT/_dmarc.thundermail.co.kr 위 URL에서 뒷 부분..