diff --git a/config/upstream.conf b/config/upstream.conf
index e18bf02..07f8f5e 100644
--- a/config/upstream.conf
+++ b/config/upstream.conf
@@ -19,6 +19,7 @@ stream {
         server xr:443;
     }
 
+    map_hash_bucket_size 128;
     map $ssl_preread_server_name $sni_name {
         #domain
         www.microsoft.com reality;