A.Createahost（A）resourcerecordforEXfourthcoffee.comontheinternalDNSServer
B.Createahost（A）resourcerecordforEXfourthcoffee.comontheexternalDNSServer
C.Createahost（A）resourcerecordforEX3.fourthcoffee.comontheinternalDNSServer
D.Createahost（A）resourcerecordforEX3.fourthcoffee.comontheexternalDNSServer
E.Createamailexchange（MX）resourcerecordforEXfourthcoffee.comontheexternalDNSserver.Setthepreferenceto10
F.Createamailexchanger（MX）resourcerecordforEXfourthcoffee.comontheinternalDNSserver.Setthepreferenceto10
G.Createamailexchanger（MX）resourcerecordforEX3.fourthcoffee.comontheexternalDNSserver.Setthepreferenceto20
H.Createamailexchanger（MX）resourcerecordforEX3.fourthcoffee.comontheinternalDNSserver.Setthepreferenceto20
参考答案：BDEG
