diff --git a/machines/akhaten/stalwart.nix b/machines/akhaten/stalwart.nix
index a8a0548..8a5b288 100644
--- a/machines/akhaten/stalwart.nix
+++ b/machines/akhaten/stalwart.nix
@@ -9,6 +9,7 @@
       };
       lookup.default.hostname = "mail.luj.fr";
       server = {
+        http.hsts = true;
         max-connections = 8192;
         hostname = "mail.luj.fr";
         tls.enable = true;