diff --git a/transport/internet/system_dialer.go b/transport/internet/system_dialer.go
index 19c2b89b..0da8d5ad 100644
--- a/transport/internet/system_dialer.go
+++ b/transport/internet/system_dialer.go
@@ -96,7 +96,7 @@ func (d *DefaultSystemDialer) Dial(ctx context.Context, src net.Address, dest ne
 		Count:    -1,
 	}
 	if sockopt != nil && (sockopt.TcpKeepAliveInterval != 0 || sockopt.TcpKeepAliveIdle != 0) {
-		TCPKeepAlive := time.Duration(-1)
+		TCPKeepAlive = time.Duration(-1)
 	}
 	dialer := &net.Dialer{
 		Timeout:   time.Second * 16,