What is OpenNTPD ?

OpenNTPD is a Unix system daemon implementing the Network Time Protocol to synchronize the local clock of a computer system with remote NTP servers. It is also able to act as an NTP server to NTP-compatible clients.

OpenNTPD is primarily developed by Henning Brauer as part of the OpenBSD project. Its design goals include being secure (non-exploitable), easy to configure, accurate enough for most purposes and with source code that can be distributed under a BSD license. Its portable version, like that of OpenSSH, is developed as a child project which adds the portability code to the OpenBSD version and releases it separately. The portable version is developed by Darren Tucker.

IPFW is one of a BSD firewall.
We can configure it very simple.
We don't need to reconfigure kernel if we don't using NATD

First add these line below in rc.conf
This will execute a IPFW if server rebooted

[code]#pico /etc/rc.conf

firewall_enable=”YES”
firewall_script=”/usr/local/etc/ipfw.rules”[/code]

Create a IPFW rules files

[code]#pico /usr/local/etc/ipfw.rules
IPF=”ipfw -q add”
ipfw -q -f flush

#loopback
ipfw add 10 allow all from any to any via lo0
ipfw add 20 deny all from any to 127.0.0.0/8