Dear all, after I have put the exchange CD in the Server 1 that contains the domain and made the ForestPrep and then DomainPrep I took the exchange CD to server 3 which is a member server of the same domain. and when I want to install it there. is gives me the following. "Setup unable to determine the DNS name of the Computer See microsoft knowlede base 817543 for information on how to correct the problem" and after I have went there I have tryed what is written there by using the "lstest /sc_reset:mydomainname " it gave me "I_netlogonControl faild: status =1355 0x54b ERROR_NO_SUCH_DOMAIN" also in the DNS advance properities I have put a check mark on 1- append parent suffix of the primary DNS suffix and in the DNS suffix for this connection "mydomain" 2- Register this DNS connection's address in DNS 3- Use this connection's DNS suffix in DNS registration Please if some one know how to solve this problem please let me know Best Regards' Hashem