diff --git a/hosts/mail/default.nix b/hosts/mail/default.nix
index 9939cf89..3c9a27fd 100644
--- a/hosts/mail/default.nix
+++ b/hosts/mail/default.nix
@@ -21,7 +21,10 @@
       organizationName = "Netzbiotop Dresden e.V.";
     };
     debug = true;
-    domains = [ "netzbiotop.org" ];
+    domains = [
+      "c3d2.social"
+      "netzbiotop.org"
+    ];
     dkimKeyBits = 2048;
     dkimSelector = "default";
     dkimSigning = true;