多项选择题
Which two external authentication methods are supported by the Junos OS for user authentication?（）
A. RADIUS B. KERBEROS C. LDAP D. TACACS+
单项选择题 What is the default export routing policy for RIP?（）
单项选择题 What is the role of route preference?（）
单项选择题 What is a valdi multicast MAC address?（）
