diff --git a/mailsystem/common.nix b/mailsystem/common.nix
new file mode 100644
index 0000000..6d9df16
--- /dev/null
+++ b/mailsystem/common.nix
@@ -0,0 +1,7 @@
+{config, ...}: let
+  cfg = config.mailsystem;
+in rec {
+  sslCertPath = "${config.security.acme.certs.${cfg.fqdn}.directory}/fullchain.pem";
+  sslKeyPath = "${config.security.acme.certs.${cfg.fqdn}.directory}/key.pem";
+  sslCertService = ["acme-finished-${cfg.fqdn}.target"];
+}