During installation I entered a primary and secondary external DNS server. I would like to remove these two now but do not know how to do this?
The answer depends on what version you have installed.
If you have a recent version, then do:
/sbin/e-smith/config delprop dnscache Forwarder
/sbin/e-smith/signal-event post-upgrade
/sbin/e-smith/signal-event reboot