diff --git a/pkgs/by-name/op/opensmtpd-filter-dkimsign/package.nix b/pkgs/by-name/op/opensmtpd-filter-dkimsign/package.nix
index 47db824282ce..c5503a8ef463 100644
--- a/pkgs/by-name/op/opensmtpd-filter-dkimsign/package.nix
+++ b/pkgs/by-name/op/opensmtpd-filter-dkimsign/package.nix
@@ -29,6 +29,7 @@ stdenv.mkDerivation (finalAttrs: {
     "HAVE_ED25519=1"
     "DESTDIR=$(out)"
     "LOCALBASE="
+    "BINDIR=/libexec/smtpd/"
   ];
 
   meta = {