diff --git a/src/types.ts b/src/types.ts
index 5efa572..2e65bfd 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -33,7 +33,7 @@ export interface Query {
   timestamp: string;
   protocol: 'http:' | 'https:';
   hostname: string;
-  port: number | undefined;
+  port: number | null;
   pathname: string;
   search: string;
 }