diff --git a/source/Classroom/Deliver/Sender_Authentication/microsoft_dmarc_changes b/source/Classroom/Deliver/Sender_Authentication/microsoft_dmarc_changes.md
similarity index 100%
rename from source/Classroom/Deliver/Sender_Authentication/microsoft_dmarc_changes
rename to source/Classroom/Deliver/Sender_Authentication/microsoft_dmarc_changes.md