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

ntp-4.2.8p8 was released on 02 June 2016. It addresses 1 high- and 4 low--severity security issues, 4 bugfixes, and contains other improvements over 4.2.8p7.

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

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Are you using Autokey in production? If so, please contact Harlan - he's got some questions for you.

4. Installing NTP

NTP may be installed from the original source code, released by the NTP Project (which was originally from the University of Delaware starting in the 1980s, and was moved to Network Time Foundation in 2011) , 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. Installing an ntp.org software release, and Getting Support

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

If you have any questions or problems installing NTP, the following resources are available:

• Community (free) support options:
  • There is a lot of support information available right here, in this wiki. There is a "Search" box on the top right-hand-side of the window.
  • Send an email to questions@lists.ntp.org
  • Ask on irc://irc.freenode.net/#ntp
  • Report a bug at https://bugs.ntp.org
• Support is available thru Network Time Foundation:
  • Via institutional membership
  • Support contracts - please send an email to info@nwtime.org

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