diff --git a/nixos/modules/services/networking/libreswan.nix b/nixos/modules/services/networking/libreswan.nix
index 3866b216f8e..c87e738d2a2 100644
--- a/nixos/modules/services/networking/libreswan.nix
+++ b/nixos/modules/services/networking/libreswan.nix
@@ -102,7 +102,7 @@ in
       serviceConfig = {
         Type = "simple";
         Restart = "always";
-        EnvironmentFile = "${pkgs.libreswan}/etc/sysconfig/pluto";
+        EnvironmentFile = "-${pkgs.libreswan}/etc/sysconfig/pluto";
         ExecStartPre = [
           "${libexec}/addconn --config ${configFile} --checkconfig"
           "${libexec}/_stackmanager start"