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1、信息安全产品配置与应用 Configuration and Application of Information Security Products,重庆电子工程职业学院| 路亚,模块八、路由交换安全配置,交换和VLAN Switching and VLAN,教学目标（ Objectives ）,1. 交换机学习主机地址 （Switche Learn Host Address） 2. 两种交换方法（Two Switching Methods） 3. 配置端口安全（Configuring Port Security） 4.密码破解（Password Recovery） 5. VLAN操作（VLA
2、N Operations） 6.配置和验证静态VLAN (Configuring and Verifying Static VLANs),地址学习（Address learning） 决定转发或过滤（Forward/filter decision） 避免环路（Loop avoidance）,交换机三种功能 （Three Switch Functions ）,交换机学习主机地址 （Switche Learn Host Address）,初始MAC地址表是空的 Initial MAC address table is empty,MAC address table,0260.8c01.1111,0
3、260.8c01.2222,0260.8c01.3333,0260.8c01.4444,E0,E1,E2,E3,A,B,C,D,交换机学习主机地址 （Switche Learn Host Address）,A向C发送帧（Station A sends a frame to Station C） 交换机将A的MAC地址和其对应的接口E0放入MAC地址表 Switch caches station A MAC address to port E0 by learning the source address of data frames 该帧向除了E0接口的所有接口泛洪 The frame fro
4、m station A to station C is flooded out to all ports except port E0,MAC address table,0260.8c01.1111,0260.8c01.2222,0260.8c01.3333,0260.8c01.4444,E0: 0260.8c01.1111,E0,E1,E2,E3,D,C,B,A,交换机学习主机地址 （Switche Learn Host Address）,D向C发送帧(Station D sends a frame to station C) 交换机将D的MAC地址和其对应的接口E3放入MAC地址表 Sw
5、itch caches station D MAC address to port E3 by learning the source Address of data frames 该帧向除了E3接口的所有接口泛洪 The frame from station D to station C is flooded out to all ports except port E3 (unknown unicasts are flooded),MAC address table,0260.8c01.1111,0260.8c01.2222,0260.8c01.3333,0260.8c01.4444,E0
6、: 0260.8c01.1111,E3: 0260.8c01.4444,E0,E1,E2,E3,D,C,A,B,交换机过滤帧（ Switches Filter Frames）,A向C发送帧 Station A sends a frame to station C 目的地址已知，帧不被泛洪 Destination is known, frame is not flooded,E0: 0260.8c01.1111,E2: 0260.8c01.2222,E1: 0260.8c01.3333,E3: 0260.8c01.4444,0260.8c01.1111,0260.8c01.2222,0260.8
7、c01.3333,0260.8c01.4444,E0,E1,E2,E3,X,X,D,C,A,B,MAC address table,两种交换方法（Two Switching Methods）,存储转发特征（Store-and-forward Feature）,1. 在转发之前整个帧被接收 The entire frame is received before any forwarding takes place. 2.由于交换开始之前要接收完整帧，较大的数据帧延迟较大 Latency is greater with larger frames because the entire frame
8、must be received before the switching process begins.,直通特征（Cut-through Feature）,1.在接收完整帧之前，帧就被转发。 The frame is forwarded through the switch before the entire frame is received. 2.最快的是只要读到目的地址就转发。 At a minimum the frame destination address must be read before the frame can be forwarded. 3.这种模式降低了延迟，但
9、是不进行检错 This mode decreases the latency of the transmission, but also reduces error detection.,直通分类（Cut-through Class）,一、快速转发（Fast-forward ） 1.快速转发提供了最低的延迟 Fast-forward switching offers the lowest level of latency. 2.只要读到目的地址，就立刻转发 Fast-forward switching immediately forwards a packet after reading th
10、e destination address.,直通分类（Cut-through Class）,二、Fragment-free （无碎片方式） 1.无碎片方式在转发之前过滤掉碰撞碎片Fragment-free switching filters out collision fragments before forwarding begins. 2.无碎片方式在转发之前要读到帧的前64字节 Fragment-free switching waits until the packet is determined not to be a collision fragment(64bytes) befo
11、re forwarding,配置SVI地址（Configuring SVI Address）,Switch(config)#interface vlan 1 Switch(config-if)#ip address 10.1.1.1 255.255.255.0 Switch(config-if)#no shutdown,配置端口安全（Configuring Port Security）,Switch(config)#int f0/1 Switch(config-if)#switchport mode access Switch(config-if)#switchport port-securi
12、ty Switch(config-if)#switchport port-security mac-address 0060.6700.dd5b Switch(config-if)#switchport port-security violation restrict Switch#sh port-security Secure Port MaxSecureAddr CurrentAddr SecurityViolation Security Action (Count) (Count) (Count) - Fa0/1 132 1 0 Restrict,密码破解（Password Recove
13、ry）,1. 拔掉电源（Unplug the power cable） 2.按下mode按钮（hold down the mode button） 3.输入flash_init （type flash_init） 4.执行dir flash: （type dir flash:） 5.重命名配置文件 （rename flash:config.text flash:config.old） 6.启动（Boot） 7.在进入setup模式提示下输入N （enter N at the prompt to start the setup program.）,密码破解（Password Recovery）,
14、8. 进入特权模式（switchenable） 9. 重命名配置文件 （rename flash:config.old flash:config.text） 10. 将配置文件拷贝到RAM中运行 （copy flash:config.text system:running-config） 11.修改密码 （enable password cisco） 12.存盘（write） 13.重启（reload）,VLAN预览（VLAN Overview）,分段Segmentation 灵活 Flexibility 安全 Security,3rd floor,2nd floor,1st floor,SA
15、LES,HR,ENG,1 VLAN =1广播域1逻辑子网 A VLAN = A broadcast domain = Logical network (subnet),VLAN操作（VLAN Operations）,每一个逻辑的VLAN就像一个独立的物理网桥 Each logical VLAN is like a separate physical bridge,VLAN操作（VLAN Operations）,Switch B,Green VLAN,Black VLAN,Red VLAN,同一个VLAN可以跨越多个交换机 VLANs can span across multiple switc
16、hes,VLAN操作（VLAN Operations）,Switch B,Green VLAN,Black VLAN,Red VLAN,Trunk,TRUNK链路携带多个VLAN的数据 Trunks carries traffic for multiple VLANs Trunks利用特定的封装来识别不同的VLAN Trunks use special encapsulation to distinguish between different VLANs,Fast Ethernet,22,VLAN成员模式（VLAN Membership Modes）,VLAN5,静态VLAN (Static VLAN)
