Which of the following steps are required in an idle scan of a closed port?

Each correct answer represents a part of the solution. Choose all that apply.

A$.$ The attacker sends a SYN$/$ACK to the zombie.

B$.$ The zombie's IP ID increases by only $1.$

C$.$ In response to the SYN$,$ the target sends a RST$.$

D$.$ The zombie ignores the unsolicited RST$,$ and the IP ID remains unchanged.

E$.$ The zombie's IP ID increases by $2.$