diff --git a/nix/nixos-module/container/bird.nix b/nix/nixos-module/container/bird.nix
index 1d33ea6..528a62b 100644
--- a/nix/nixos-module/container/bird.nix
+++ b/nix/nixos-module/container/bird.nix
@@ -109,7 +109,7 @@ in
         protocol radv {
           rdnss ${config.site.net.serv.hosts6.dn42.dnscache};
 
-          ${lib.concatMapStrings (net:
+          ${lib.concatMapStrings (net: ''
             interface "${net}" {
               min ra interval 10;
               max ra interval 60;
@@ -125,7 +125,7 @@ in
 
               dnssl "${config.site.net.${net}.domainName}";
             };
-          ) ipv6RouterNets}
+          '') ipv6RouterNets}
         }
       ''}