diff --git a/lass/2configs/exim-retiolum.nix b/lass/2configs/exim-retiolum.nix
new file mode 100644
index 000000000..ea2f553b8
--- /dev/null
+++ b/lass/2configs/exim-retiolum.nix
@@ -0,0 +1,14 @@
+{ config, lib, pkgs, ... }:
+
+with config.krebs.lib;
+
+{
+  krebs.exim-retiolum.enable = true;
+  krebs.setuid.sendmail = {
+    filename = "${pkgs.exim}/bin/exim";
+    mode = "4111";
+  };
+  krebs.iptables.tables.filter.INPUT.rules = [
+    { predicate = "-i retiolum -p tcp --dport smtp"; target = "ACCEPT"; }
+  ];
+}