diff --git a/nix/nixos-module/container/bird.nix b/nix/nixos-module/container/bird.nix
index 5d7f328..fb2bbce 100644
--- a/nix/nixos-module/container/bird.nix
+++ b/nix/nixos-module/container/bird.nix
@@ -72,15 +72,12 @@ in
             else ''
               export all;
               import filter {
-                ${lib.concatMapStrings (net:
-                  lib.optionalString (
-                    config.site.net.${net}.subnet4 or null != null
-                  ) ''
-                    if net ~ [ ${config.site.net.${net}.subnet4} ] then {
-                      # Learn route of local network ${net}
-                      accept;
-                    }
-                  '') (builtins.attrNames hostConf.interfaces)}
+                ${lib.concatMapStrings (net: ''
+                  if net ~ [ ${lib.concatStringsSep " " (builtins.attrValues config.site.net.${net}.subnets6)} ] then {
+                    # Learn route of local network ${net}
+                    accept;
+                  }
+                '') (builtins.attrNames hostConf.interfaces)}
                 reject;
               };
             ''}