diff --git a/blobserver/go/camlistored.go b/blobserver/go/camlistored.go
index 18baa2bdd..1db75e022 100644
--- a/blobserver/go/camlistored.go
+++ b/blobserver/go/camlistored.go
@@ -292,8 +292,17 @@ func handlePreUpload(conn *http.Conn, req *http.Request) {
 	ret := make(map[string]interface{})
 	ret["maxUploadSize"] = 2147483647 // 2GB.. *shrug*
 	ret["alreadyHave"] = haveVector.Copy()
-	ret["uploadUrl"] = "http://localhost:3179/camli/upload"
 	ret["uploadUrlExpirationSeconds"] = 86400
+
+	if len(req.Host) > 0 {
+		scheme := "http" // TODO: https
+		ret["uploadUrl"] = fmt.Sprintf("%s://%s/camli/upload",
+			scheme, req.Host)
+	} else {
+		ret["uploadUrl"] = "/camli/upload"
+	}
+
+
 	returnJson(conn, ret)
 }