---
title: "Securing NTP"
slug: "securing-ntp"
updated: 2026-06-30T04:41:25Z
published: 2026-06-30T04:41:25Z
canonical: "docs.serversaustralia.com.au/securing-ntp"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://docs.serversaustralia.com.au/llms.txt
> Use this file to discover all available pages before exploring further.

# Securing NTP

Following on from DNS Amplification DDoS attacks, more recently NTP services are being utilised for Amplification DDoS attacks to reflect traffic against other networks. There are two major issues, which is "Monlist", and "Readvar". Below are some basic steps, to reduce the effectiveness of these kinds of attacks, by locking down the default restrictions within the configuration which can be read up further on at the below URL's: [NTP-Version](https://www.shadowserver.org/wiki/pmwiki.php/Services/NTP-Version) [NTP-Monitor](https://www.shadowserver.org/wiki/pmwiki.php/Services/NTP-Monitor)

## **Within ntpd on *nix**

To Resolve most issues, you would need to add the below to /etc/ntp.conf. (This should resolve both **monlist**, and **readvar** issues).

```shell
restrict default ignore

disable monitor

disable bclient
```

Then restart the ntpd service (or ntp on some OS'). To test that this has worked, you can use the following queries from a remote Linux Machine:

## **Readvar:**

```shell
ntpq -c rv [ip]
```

## **Monlist:**

```shell
ntpdc -n -c monlist [ip]
```

And expect a "connect timeout" error, if your work has been successful to secure the NTP service.