diff --git a/nix/nixos-module/container/bird.nix b/nix/nixos-module/container/bird.nix
index f618924..952f31c 100644
--- a/nix/nixos-module/container/bird.nix
+++ b/nix/nixos-module/container/bird.nix
@@ -220,9 +220,8 @@ in
                   if config.site.net.${net}.ospf.secret != null
                   then ''
                     interface "${net}" {
-                      # TODO: enable when all bird 1.x have shut down
-                      #authentication cryptographic;
-                      #password "${config.site.net.${net}.ospf.secret}";
+                      authentication cryptographic;
+                      password "${config.site.net.${net}.ospf.secret}";
                     };
                   ''
                   else builtins.concatStringsSep "\n" (
@@ -260,8 +259,8 @@ in
                         # Become the designated router
                         priority 10;
 
-                        #authentication cryptographic;
-                        #password "${config.site.net.${net}.ospf.secret}";
+                        authentication cryptographic;
+                        password "${config.site.net.${net}.ospf.secret}";
                       };
                     ''
                   ) hostConf.interfaces
@@ -291,8 +290,8 @@ in
                         # Enable OSPF only on interfaces with a secret.
                         lib.optionalString (config.site.net.${net}.ospf.secret != null) ''
                           interface "${net}" instance ${toString config.site.hosts.${upstream}.ospf.upstreamInstance} {
-                            #authentication cryptographic;
-                            #password "${config.site.net.${net}.ospf.secret}";
+                            authentication cryptographic;
+                            password "${config.site.net.${net}.ospf.secret}";
                           };
                         ''
                       ) hostConf.interfaces