diff --git a/pkgs/tools/networking/nss-mdns/default.nix b/pkgs/tools/networking/nss-mdns/default.nix
index f0c47fe945e1..5b6c90e63bdf 100644
--- a/pkgs/tools/networking/nss-mdns/default.nix
+++ b/pkgs/tools/networking/nss-mdns/default.nix
@@ -22,6 +22,8 @@ stdenv.mkDerivation rec {
     "--enable-avahi"
     # Connect to the daemon at `/var/run/avahi-daemon/socket'.
     "--localstatedir=/var"
+    # Read configuration at `/etc/mdns.allow`, not `$out/etc/mdns.allow`.
+    "--sysconfdir=/etc"
   ];
 
   meta = {