I use DGSN as a master DNS ,it is " ns3.XXX.co.th" . and now it works. i have the other two servers . I register them as ns1.XXX.co.th and ns2.XXX.co.th. please help me to configure them as ns1.XXX.co.th and ns2.XXX.co.th .Do i have to go to create slave zone? can you give an example please? thank you very much.