(This book specifically explains the method of configuring the access table of the CISCO router, including the basic knowledge of the network, the basic knowledge of access control, the common knowledge of the software and hardware of the CISCO router, and the usual configuration method of the CISCO router. The main point introduces the access control list of CISCO, including dynamic access list, reflexive access control list, time-based access list and context-based access control, etc., and discusses some other security common sense. This book narrates clearly, practicability is strong, it is a rare and rare good book for network administrators and readers who are interested in CISCO security policy.)