diff --git a/lib/server.js b/lib/server.js
index 09ab49ca0..38336d1b7 100644
--- a/lib/server.js
+++ b/lib/server.js
@@ -291,7 +291,14 @@ Server.prototype.generateId = function (req) {
  */
 
 Server.prototype.handshake = function (transportName, req) {
-  var id = this.generateId(req);
+  var id;
+
+  try {
+    id = this.generateId(req);
+  } catch (e) {
+    sendErrorMessage(req, req.res, e.message || Server.errors.BAD_REQUEST);
+    return;
+  }
 
   debug('handshaking client "%s"', id);