DC and ADC w2003 Server Ent crash main dc how is work adc

Hai,

Every body,

I have one question for i have one main domain and one additional domain suposse my main domain crash so how can i implement for my additional domain same work, main domain connected for exchange server so how how can i implement for my main dc crash how can i up additional domain Kindly i need help for this task Thanks for your’s supports

Kindly i need your’s help

Best Regards,
Mohammed Aijaz