diff --git a/authoritative-dns.nix b/authoritative-dns.nix
index 0067024..2da8b7d 100644
--- a/authoritative-dns.nix
+++ b/authoritative-dns.nix
@@ -34,7 +34,7 @@ in {
   options.services.authoritative-dns = with types; {
     enable = mkEnableOption "Enable authoritative DNS service.";
 
-    identity = mkOPtion {
+    identity = mkOption {
       type = str;
       description = "The identity (CH TXT ID.SERVER) of this host.";
     };