diff --git a/lib/server/parse-http.js b/lib/server/parse-http.js
index 9e83a59..24c3c69 100644
--- a/lib/server/parse-http.js
+++ b/lib/server/parse-http.js
@@ -24,7 +24,9 @@ function parseHttpRequest (req, opts) {
     params.port = Number(params.port)
     if (!params.port) throw new Error('invalid port')
 
-    params.left = Number(params.left) || Infinity
+    params.left = Number(params.left)
+    if (isNaN(params.left)) params.left = Infinity
+
     params.compact = Number(params.compact) || 0
     params.numwant = Math.min(
       Number(params.numwant) || common.DEFAULT_ANNOUNCE_PEERS,