diff --git a/static/.well-known/mta-sts.txt b/static/.well-known/mta-sts.txt
new file mode 100644
index 0000000..4425a8b
--- /dev/null
+++ b/static/.well-known/mta-sts.txt
@@ -0,0 +1,6 @@
+version: STSv1
+mode: enforce
+max_age: 86400
+mx: mxext1.mailbox.org
+mx: mxext2.mailbox.org
+mx: mxext3.mailbox.org