NTP users are strongly urged to take immediate action to ensure that their NTP daemons are not susceptible to use in a distributed denial-of-service (DDoS) attack. Please also take this opportunity to defeat denial-of-service attacks by implementing ingress and Egress filtering through BCP38.

The final two security bugs reported by Google's Security Team have been fixed as of ntp-4.2.8p1.

A new set of mode 6 vulnerabilities has been discovered and, while these vulnerabilities can be reduced by making sure you have restrict default … noquery in your ntp.conf file, the best and most complete way to avoid these vulnerabilities is to install and deploy ntp-4.2.8p1 which was released on 04 February 2015.

Please see the NTP Security Notice for vulnerability and mitigation details.

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4. Installing NTP

NTP may be installed from the original source code, released by the NTP Project at the University of Delaware, or through pre-packaged or pre-compiled versions which may be available from your Operating System vendor/aggregator/distributor.

The instructions shown below for specific operating systems are presented as a courtesy and may not be up to date. These instructions presume that you have properly configured that operating systems package management infrastructure. Users are advised to consult their their operating system documentation for current installation instructions.

4.1. The NTP Project Reference Implementation Distribution

Users attempting to install NTP from source code should have some experience compiling software on UNIX or a Unix-like operating system.

The following software is used when installing NTP source code:

• A C compiler
• make (note that on some platforms, building outside of the main source directory requires GNU make.)
• tar
• gunzip
• libcap (note: needed for linux only if you wish to enable linux capabilities to drop root privileges and chroot ntpd)

4.1.1.

1. Download and unpack a tarball from SoftwareDownloads or The NTP Project Download Page
2. Read and follow the directions in the INSTALL file
3. See ConfiguringNTP for information about how to configure NTP
4. Add the init scripts, etc., to make NTP start at boot time

4.2. Debian GNU/Linux

4.2.1. NTP Pool Client

1. apt-get install ntp

4.2.2. Custom Configuration

1. apt-get install ntp
2. Edit /etc/ntp.conf (see ConfiguringNTP)
3. Create any required symlinks for your ref-clock if you are using one
4. Restart ntpd with /etc/init.d/ntp-server restart

4.3. FreeBSD

1. cd /usr/ports/net/ntp
2. make install clean
3. Edit /etc/ntp.conf (see ConfiguringNTP)
4. Edit /etc/rc.conf
5. Create any required symlinks for your ref-clock (if you are using one)
6. Start ntpd with /etc/rc.d/ntpd start

4.4. NetBSD

1. ...

4.5. OpenBSD

1. ...

4.6. Microsoft Windows

1. Instructions for installing on Windows