Hi,
I suppose that you want to use SME as your local DHCP server, but not as your domain server (or at least, not as the only dns server).
The dhcpd configuration is in the file /etc/dhcpd.conf
from man dhcpd.conf :
option domain-name-servers ns1.isc.org, ns2.isc.org;
/etc/dhcpd.conf is a templatised file.
The fragment of interrest is :
/etc/e-smith/templates/etc/dhcpd.conf/25DomainNameServers
You should copy this file in the template-custom directory :
mkdir -p /etc/e-smith/templates-custom/etc/dhcpd.conf
cp /etc/e-smith/templates/etc/dhcpd.conf/25DomainNameServers /etc/e-smith/templates-custom/etc/dhcpd.conf/25DomainNameServers
Then, with your favorite file editor, just change the line to set the DNS servers you want.
you now need to expand the templete (to create a new /etc/dhcpd.conf file)
/sbin/e-smith/expand-template /etc/dhcpd.conf
And finally, you must restart the dhcpd daemon :
service dhcpd restart
That should do the work.
HTH,