Edit the /etc/ntp.conf file:

restrict default ignore
restrict 192.168.42.1 mask 255.255.255.255 nomodify notrap noquery
restrict 127.0.0.1
server ntp.brimbelle.org

Then the /etc/config/ntp.options to just have:

-f /etc/ntp.drift
-c /etc/ntp.conf

Restart ntpd:

/etc/init.d/ntp restart

Test:

$ ntpq -p
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
*192.168.42.1    net1.web.yas-on  3 u   26   64  177    3.436   29.604   0.056