diff --git a/simple-tcp-proxy.go b/simple-tcp-proxy.go
index ed78748..032ec3b 100644
--- a/simple-tcp-proxy.go
+++ b/simple-tcp-proxy.go
@@ -11,6 +11,8 @@ import (
 	"strings"
 )
 
+const ConfigFileName = "tcp_listen_config.json"
+
 type ConnErrorType int32
 
 const (
@@ -135,13 +137,14 @@ func printHelpMessage() {
 	if tcpListenConfigJSON, err := json.Marshal(tcpListenConfig); err == nil {
 		var out bytes.Buffer
 		if err := json.Indent(&out, tcpListenConfigJSON, "", "  "); err == nil {
-			fmt.Printf("[INFO] Sample JSON config [tcp_listen_config.json]:\n%s\n", string(out.Bytes()))
+			fmt.Printf("[INFO] Sample JSON config [%s]:\n%s\n", ConfigFileName, string(out.Bytes()))
 		}
 	}
 }
 
 func readConfigFile() (*TcpListenConfig, error) {
-	configFile, err := os.Open("tcp_listen_config.json")
+	fmt.Printf("[INFO] Load config: %s\n", ConfigFileName)
+	configFile, err := os.Open(ConfigFileName)
 	if err != nil {
 		return nil, err
 	}