单项选择题
A. The NAT action of off is only supported for destination NAT rule-sets.
B. The NAT action of off is only supported for source NAT rule-sets.
C. The NAT action of off is useful for detailed control of NAT.
D. The NAT action of off is useful for disabling NAT when a pool is exhausted
多项选择题 Which two content-filtering features does FTP support?（） (Choose two.)
单项选择题 Using a policy with the policy-rematch flag enabled, what happens to the existing and new sessions when you change the policy action from permit to deny?（）
单项选择题 Which statement is true when express AV detects a virus in TCP session?（）