diff --git a/src/infra/bonjour-discovery.ts b/src/infra/bonjour-discovery.ts
index a9b9f9a58..ebb77a9b1 100644
--- a/src/infra/bonjour-discovery.ts
+++ b/src/infra/bonjour-discovery.ts
@@ -270,7 +270,7 @@ async function discoverWideAreaViaTailnetDns(
 
   if (!nameserver || ptrs.length === 0) return [];
   if (remainingMs() <= 0) return [];
-  const nameserverArg = `@${nameserver}`;
+  const nameserverArg = `@${String(nameserver)}`;
 
   const results: GatewayBonjourBeacon[] = [];
   for (const ptr of ptrs) {