diff --git a/lib/browserid/http_forward.js b/lib/browserid/http_forward.js
index 3eec38ed9b127280b6ed2a39f892e8930f7c095a..5db137c2c8720ecca9e19913e29630d6fed93ecf 100644
--- a/lib/browserid/http_forward.js
+++ b/lib/browserid/http_forward.js
@@ -16,14 +16,14 @@ module.exports = function(dest, req, res, cb) {
     path: u.pathname,
     method: req.method
   }, function(pres) {
-    var hdrs = {};
-    [ 'access-control-allow-origin', 'content-type', 'content-length' ].forEach(function(key) {
-      if (pres.headers.hasOwnProperty(key)) {
-        hdrs[key] = pres.headers[key];
-      }
-    });
-    res.writeHead(pres.statusCode, hdrs);
-
+    res.statusCode = pres.statusCode;
+    // forward along Content-Type and Content-Length, if available
+    if (pres.headers.hasOwnProperty('content-type')) {
+      res.setHeader('Content-Type', pres.headers['content-type']);
+    }
+    if (pres.headers.hasOwnProperty('content-length')) {
+      res.setHeader('Content-Length', pres.headers['content-length']);
+    }
     pres.on('data', function (chunk) {
       res.write(chunk);
     }).on('end', function() {