diff --git a/pkgs/tools/networking/fdm/default.nix b/pkgs/tools/networking/fdm/default.nix
index 3984922abe2..54e20539066 100644
--- a/pkgs/tools/networking/fdm/default.nix
+++ b/pkgs/tools/networking/fdm/default.nix
@@ -27,5 +27,6 @@ stdenv.mkDerivation rec {
     platforms = with platforms; linux;
     homepage = https://github.com/nicm/fdm;
     downloadPage = https://github.com/nicm/fdm/releases;
+    license = licenses.isc;
   };
 }