阅读下面的短文,回答问题 [When an IP packet arrives at a router, generally the router looks at the destination address of the packet, and forwards the packet to one of its network interfaces. The forwarding decision is usually done by looking up the destination address from another data structure called a forwarding table. The forwarding table is created by the router using the routing table and possible routing policies existing in the router. The router then creates a table where it lists which networks are accessible through which of the routers network interfaces. An IP router looks at every IP packet individually and does the forwarding decision on a packet-by-packet basis. If something changes in the routers routing table, a packet can take a different route from a preceding packet even if it has the same destination.] From the paragraph above,we can see that the router ( ) a forwarding table according to the routing table and possible routing policies existing in the router. When an IP packet arrives at a router, the ( ) part of packet is normally checked by the router. An IP router checks every IP Packet individually and makes the forwarding decision based on ( ).A.is generating B.generate C.is generated D.generates A.forwarding table B.network interfaces C.routing policies D.destination address A.the destination address and network interfaces B.forwarding table and network interfaces C.the destination address and forward table D.routing policies and routing table

阅读下面的短文,回答问题 [When an IP packet arrives at a router, generally the router looks at the destination address of the packet, and forwards the packet to one of its network interfaces. The forwarding decision is usually done by looking up the destination address from another data structure called a forwarding table. The forwarding table is created by the router using the routing table and possible routing policies existing in the router. The router then creates a table where it lists which networks are accessible through which of the router’s network interfaces. An IP router looks at every IP packet individually and does the forwarding decision on a packet-by-packet basis. If something changes in the router’s routing table, a packet can take a different route from a preceding packet even if it has the same destination.] From the paragraph above,we can see that the router ( ) a forwarding table according to the routing table and possible routing policies existing in the router. When an IP packet arrives at a router, the ( ) part of packet is normally checked by the router. An IP router checks every IP Packet individually and makes the forwarding decision based on ( ).

A.is generating B.generate C.is generated D.generates A.forwarding table B.network interfaces C.routing policies D.destination address A.the destination address and network interfaces B.forwarding table and network interfaces C.the destination address and forward table D.routing policies and routing table


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阅读以下说明,回答问题1、问题2、问题3和问题4,将解答填入对应栏内。[说明]RIP(Routing Information Protocols,路由信息协议)是使用最广泛的距离向量协议,它是由施乐(Xerox)在70年代开发的。当时,RIP是XNS(Xerox Network Service,施乐网络服务)协议簇的一部分。TCP/IP版本的RIP是施乐协议的改进版。RIP最大的特点是无论实现原理还是配置方法,都非常简单。以下是RIP配置的部分清单。Router>enable (1)Enter configuration commands,one per line.End with CNTL/Z. (2)Router (config) interfacee 0/1 (3)Router (config-if) ipaddress172.16.1.2 255.255.255.0Router (config-if)//为了便于配置和记忆,还可以给每个端口添加一些描述信息。如下所示,在端口局部配置模式下使用description命令。Router ( config-if ) description connect to CIU (8)Router (config-if) endRouter......Routercopy mnning-config startup-config (12)Building configuration...[OK]Router......Router (config) linc console 0 (17)Router (config-line) login (18)Router (config-line) password cisco (19)Router (config-line) exit (20)Router (config) line vty 0 4 (21)Router (config-line) login (22)Router (config-line) password cisco (23)Router (config-line) exit (24)Routerping 192.168.4.2Type escape sequence to abort.Sending 5, 100-byte ICMP Ethos to 192.168.4.2, timeout is 2 seconds:!!!!!Success rate is 100 percent (5/5) , round-trip min/avg/max = 24/25/28 msRoutertraceroute 192.168.4.2Type escape sequence to abort.Tracing the route to 192.168.4.21 192.168.2.2 16 msec 16 msecRoutertelnet 192.168.4.2Trying 192.168.4.2 ... OpenUser Access VerificationPassword:Router >Routerdebug ip rip (41)RIP protocol debugging is onRouter请解释第(8)、(12)、(41)行的意义及(17)~(20)与(21)~(24)行的作用。

以下是指定VPN在建立连接时协商IKE使用的策略,阅读下面的配置信息,解释(6)、(7)处的命令。Router(config) crypto isakmp policy 10(定义策略为10)Router(config-isakmp) hash md5(6)Router(config-isakmp) authentication prc-sharc(7)Router(config-isakmp) exitRouter(config) crypto isakmp key cisco123 address 0,0.0.0 0.0.0.0(配置预共享密钥为cisc0123,对等端为所有IP)

图是某公司利用Intemet建立的VPN。分部l采用DDN通过一台路由器接入Intemet。阅读下面的路由配置信息,将(1)一(3)处标识的语句进行解释。Routeren (进入特权模式)Routerconfig terminal (进入全局配置模式)Router(config)enable secret cisco (设置特权口令)Router(config)line vty 0 4Router(config—line)password goodbad (1)Router(config—line)exitRouter(config)interface eth 0/0 (进入以太网接口配置模式)Router(config—if)ip address 202.117.1.1 255.255.255.0 (设置IP地址和掩码)Router(config—if)no shutdown (启用以太网接口)Router(config—if)exitRouter(config)interface serialO/O (进入串口配置模式)Router(config—if)ip address 211.175.132.10 255.255.255.252 (设置IP地址和掩码)Router(config—if)bandwidth 256 (指定带宽为256Kbps)Router(config—if)encapsulation PPP (2)Router(config—if)no cdp enable (3)Router(config—if)no shutdown (启用serial接口)Router(config—-if)exitRouter(config)分部1的路由器配置为ethemet0/0端口接内部网络,serialO/O端口接外部网络。下列配置指定内外网端口,完成下列配置。Router(config—if)inter eth0/0Router(config—if)(4)Router(config—if)inter serial0/0Router(config—if)(5)Router(config—if)exitRouter(config—if)

【说明】图5-1是某公司利用Internet建立的VPN【问题1】(4分)使用VPN技术,是为了保证内部数据通过Internet安全传输,VPN技术主要采用哪些技术来保证数据安全【问题2】(3分)分部1采用DDN通过一台路由器接入Internet。 阅读下面的路由配置信息,将(1)~(3)处标识的语句进行解释。Routeren (进入特权模式)Router config terminal (进入全局配置模式)Router(config)enable secret cisco (设置特权口令)Router(config)line vty 04Router(config-line)password goodbad ___(1)___Router(config-line)exitRouter(config) interface eth 0/0 (进入以太网接口配置模式)Router(config-if) ip address 202.117.1.1 255.255.255.0 (设置IP地址和掩码)Router(config-if)no shutdown (启用以太网接口)Router(config-if)exitRouter(confi9)interface serialO/O (进入串口配置模式)RouteIconfig-if)ip address 211.175.132.10 255.255.255.252 (设置IP地址和掩码)Router(config-if) bandwidth 256 (指定带宽为256k)Router(config-if) encapsulation PPP ___(2)___Router(config-if) no cdpenable ___(3)___Router(config-if) no shutdown (启用serial接口)Router(config-if) exitRouter(config)【问题3】(4分)分部1的路由器配置为ethernet0/0端口接内部网络,serialO/O端口接外部网络。下列配置指定内外网端口,完成下列配置,将答案填写在答题纸相应的位置。Router(config-if) inter ethO/ORouter(config-if) ___(4)___Router(config-if) inter serial0/0Router(config-if) ___(5)___Router(config-if) exitRouter(config-if)【问题4】(4分)以下是指定VPN在建立连接时协商IKE使用的策略,阅读下面的配置信息,解释(6)、(7)处的命令,将答案填写在答题纸相应的位置。Router(config-if) crypto isakmp policy 10 (定义策略为10)Router(config-isakmp) hash md5___(6)___Router(config-imp) authentication pre-share___(7)___Router(config-isakmp) exitRouter(config)crypto isakmp keycisc0 123 address 0.0.0.00.0.0.0 (配置预共享密钥为cisco123,对等端为所有IP)

试题四(共15分)阅读以下说明,回答问题1至问题5,将解答填入答题纸对应的解答栏内。【说明】某公司两分支机构之间的网络配置如图4-1所示,为保护通信安全,在路由器router-a和router-b上配置IPSec安全策略,对192.168.8.0/24网段和 192.168.9.0/24网段之间的数据进行加密处理。【问题1】(3分)为建立两分支机构之间的通信,请完成下面的路由配置命令。router-a (config) iproute 0.0.0.0 0.0.0.0 (1)router-b(config)iproute 0.0.0.0 0.0.0.0 (2)【问题2】(3分)下面的命令是在路由器router-a中配置IPSec隧道。请完成下面的隧道配置命令。router-a(config) crypto tunnel tun1 (设置IPSec隧道名称为tunl)router-a(config-tunnel) peer address (3) (设置隧道对端IP地址,router-a(config-tunnel)local address (4) 设置隧道本端IP地址)router-a(config-tunnel) set auto-up (设置为自动协商)router-a(config-tunnel) exit (退出隧道设置)【问题3】(3分)router-a 与 router-b之间采用预共享密钥“12345678”建立IPSec关联,请完成下面配置router-a(config) cryptike key 12345678 addressrouter_a(config)cryt ike key 12345678 addresS (5)router-b(config) crypt ike key 12345678 address (6)【问题4】(3分)下面的命令在路由器router-a中配置了相应的IPSec策略,请说明该策略的含义。router-a(config) crypto policyplrouter-a(config-policy) flow192.168.8.0255.255.255.0192.168.9.0.255.255.255.255.0ip tunnel tunlrouter-a(config-policy)exit【问题5】(3分)下面的命令在路由器router-a中配置了相应的IPSec提议。router-a(config) crypto ipsec proposal secplrouter-a(config-ipsec-prop) esp 3des shalrouter-a(config-ipsecprop)exit该提议表明:IPSec采用ESP报文,加密算法 (7) ,认证算法采用 (8) 。

管理员在Router上进行了如下配置,完成之后,在该路由器的G1/0/0接口下连接了一台交换机,则关于此主机的IP地址描述正确的是( )。[Router]ip pool pool1[Router-ip-pool-pool1]network 10.10.10.0 mask 255.255.255.0[Router-ip-pool-pool1]gateway-list 10.10.10.1[Router-ip-pool-pool1]quit[Router]ip pool pool2[Router-ip-pool-pool2]network 10.20.20.0 mask 255.255.255.0[Router-ip-pool-pool2]gateway-list 10.20.20.1[Router-ip-pool-pool2]quit[Router]interface GigabitEthernet 1/0/0[Router-GigabitEthernet 1/0/0]ip address 10.10.10.1.24[Router-GigabitEthernet 1/0/0]dhcp select globalA.获取的IP地址属于10.10.10.0/24网络B.获取的IP地址属于10.20.20.0/24网络C.主机获取不到IP地址D.获取的IP地址可能属于10.10.10.0/24网络,也可能属于10.20.20.0/24网络

管理员在Router上进行了如下配置,完成之后,在该路由器的G1/0/0接口下连接了一台交换机,则关于此主机的IP地址描述正确的是( )。[Router]ip pool pool1[Router-ip-pool-pool1]network 10.10.10.0 mask 255.255.255.0[Router-ip-pool-pool1]gateway-list 10.10.10.1[Router-ip-pool-pool1]quit[Router]ip pool pool2[Router-ip-pooA.获取的IP地址属于10.10.10.0/24网络B.获取的IP地址属于10.20.20.0/24网络C.主机获取不到IP地址D.获取的IP地址可能属于10.10.10.0/24网络,也可能属于10.20.20.0/24网络

在静态NAT转换中将IP地址192.168.1.7转换成IP地址200.8.7.3的命令是:A.Router(config)#ip nat inside source static 192.168.1.7 200.8.7.3B.Router#ip nat inside source static 192.168.1.7 200.8.7.3C.Router(config)#ip nat inside source static 200.8.7.3 192.168.1.7D.Router#ip nat inside source static 200.8.7.3 192.168.1.7

2、在静态NAT转换中将IP地址192.168.1.7转换成IP地址200.8.7.3的命令是:A.Router(config)#ip nat inside source static 192.168.1.7 200.8.7.3B.Router#ip nat inside source static 192.168.1.7 200.8.7.3C.Router(config)#ip nat inside source static 200.8.7.3 192.168.1.7D.Router#ip nat inside source static 200.8.7.3 192.168.1.7

【单选题】能配置 IP 地址的提示符是A.Router>B.Router#C.Router(config)#D.Router(config-if)#