1. Prerequisites
----------------

You will need an entropy (randomness) source.  If your OS has arc4random or
getentropy then that is ideal. Otherwise, you can use the builtin arc4random
implementation or the one built into LibreSSL.

2. Building / Installation
--------------------------

To install OpenNTPD with default options:

./configure
make
make install

This will install the OpenNTPD binary in /usr/local/sbin, configuration
files in /usr/local/etc. To specify a different installation prefix,
use the --prefix option to configure:

./configure --prefix=/opt
make
make install

Will install OpenNTPD in /opt/{etc,sbin}. You can also override
specific paths, for example:

./configure --prefix=/opt --sysconfdir=/etc/ntp
make
make install

This will install the binaries in /opt/sbin, but will place the
configuration files in /etc/ntp.

OpenNTPD always uses Privilege Separation (ie the majority of the
processing is done as a chroot'ed, unprivileged user).

This requires that a user, group and directory to be created for it.
The user should not be permitted to log in, and its home directory
should be owned by root and be mode 755.

If you do "make install", the Makefile will create the directory with
the correct permissions and will prompt you for the rest if required.
If, however, you need to perform all of these tasks yourself (eg if you
are moving the built binaries to another system) then you will need to
do something like the following (although the exact commands required
for creating the user and group are system dependant):

# groupadd _ntp
# useradd -g _ntp -s /sbin/nologin -d /var/empty/ntp -c 'OpenNTP daemon' _ntp
# mkdir -p /var/empty/ntp
# chown 0 /var/empty/ntp
# chgrp 0 /var/empty/ntp
# chmod 0755 /var/empty/ntp

There are a few options to the configure script in addition to the ones
provided by autoconf itself:

--with-privsep-user=[user]
	Specify unprivileged user used for privilege separation.  The default
	is "_ntp".

--with-privsep-path=path
	Normally ntpd will always use the home directory of the privsep user
	to chroot to, however use of this option will cause ntpd to always
	use the specified directory.

If you need to pass special options to the compiler or linker, you
can specify these as environment variables before running ./configure.
For example:

CFLAGS="-O -m486" LDFLAGS="-s" LIBS="-lrubbish" LD="/usr/foo/ld" ./configure


3. Configuration
----------------

The runtime configuration files are installed by in ${prefix}/etc or
whatever you specified as your --sysconfdir (/usr/local/etc by default).

If no configuration file exists, the default one is used.  The default
configuration file uses a selection of publicly accessible "pool" servers
(see http://twiki.ntp.org/bin/view/Servers/NTPPoolServers).


4. Problems?
------------

If you experience problems compiling, installing or running OpenNTPD,
please report the problem to the address in the README file.