email security | KC's Blog

Blocking Attachments based on the File Extension on Microsoft 365

May 9, 2021May 9, 2021 Kent ChenMicrosoft

After getting a lot of phishing emails with suspicious HTML attachments, I was scared and decided to pull the trigger to get them blocked on the server level so no one will see them in their Outlook inbox. Sign into Microsoft 365 Portal and go to Exchange Admin Center. Click Mail Flow on the left-side pane, and click the little […]

Authentic Emails with SPF, DKIM, and DMARC

April 29, 2019May 7, 2019 Kent ChenInternet

SPF, DKIM, and DMARC are different methods to authenticate your email to serve one dedicated purpose, detecting forged sender address in emails used in phishing or spam. SPF, Sender Policy Framework, allows the receiver to check that an email claiming from a specific domain comes from an IP address authorized by that domain’s admin. A typical SPF record is a […]