diff --git a/modules/default.nix b/modules/default.nix
index 8abc53c..9e6cb88 100644
--- a/modules/default.nix
+++ b/modules/default.nix
@@ -99,6 +99,10 @@ in
     # NixOS state version (see https://nixos.wiki/wiki/FAQ/When_do_I_update_stateVersion)
     system.stateVersion = "20.03";
 
+    # When this is set to true (default), routing everything through a
+    # wireguard tunnel does not work.
+    networking.firewall.checkReversePath = "loose";
+
     nix = {
       nixPath = [
         "/var/src" # pinned nixpkgs and configuration