The mailserver is currently called fred, while the primary MX record points to

What must be done to direct email towards fred?

A. Add an A record for mailhost to fred's IP address.
B. Add a CNAME record from mailhost to fred
C. Add another MX record pointing to fred's IP address.
D. Add a PTR record from mailhost to fred.



HOST     ADDRESS              TYPE
mailhost        A   #這是題目問的應該要增加的A記錄,讓「」對應到「」這個IP位址,也就是「fred」。
@ MX  #主機名稱「@」表示所有寄到「」的信都會傳給「」。如果是使用「*」則表示所有寄到「*」的信都會傳給「」。