diff --git a/config.env.example b/config.env.example
index d65a914b..a9c11ecf 100644
--- a/config.env.example
+++ b/config.env.example
@@ -4,7 +4,8 @@ S3_ACCESS_KEY=
 S3_SECRET_KEY=
 S3_BUCKET=
 
-# With Docker, use "redis".
+# With Docker, use "redis", use "localhost" when you 
+# run Redis on your own device.
 REDIS_HOST=redis
 REDIS_PORT=6379