ip unnumbered 命令配置

Ip unnumbered 命令、配置 “借用IP地址”实际就是:一个接口上没有配置IP地址,但是还想使用该接口。就向其它有IP地 址的接口借一个IP地址来。如果被借用接口有多个IP地址,只能借来主IP地址。如果被借用接口没有 IP地址,则借用接口的IP地址为0.0.0.0。该功能通过Ip unnumbered命令来实现。 例子: loopback0 1.1.1.1/24<------>R1<-s2/1--------PPP----------s2/1->R2<---------->loopback0 2.2.2.2/24 实验说明: 通过二层PPP封装可以实现地址借用,地址借用可节省可用IP地址,本实验R1,R2 串口不配地址,通过ppp封装,可借用内网IP地址,loopback口模拟内网。 实验要求: 通过借用地址让两台路由器之间可正常通信。 实验过程: 第一步:配置R1R2预配置 Router>en Router#conf t Enter configuration commands, one per line. End with CNTL/Z. Router(config)#hos R1 R1(config)#no ip domain-loo R1(config)#line con 0 R1(config-line)#no exec-t R1(config-line)#logg syn R1(config-line)#end R1# Router>en Router#conf t Enter configuration commands, one per line. End with CNTL/Z. Router(config)#hos R2 R2(config)#no ip domain-loo R2(config)#line con 0 R2(config-line)#no exec-t R2(config-line)#logg syn R2(config-line)#end R2# 第二步:配置内网接口地址and封装串口与地址借用 R1#conf t Enter configuration commands, one per line. End with CNTL/Z. R1(config)#int loo 0 R1(config-if)# R1(config-if)#ip add 1.1.1.1 255.255.255.0 //模拟内网地址 R1(config-if)#exi R1(config)#int s 2/1 R1(config-if)#en ppp //封装接口地址ppp R1(config-if)# R1(config-if)#ip unn R1(config-if)#ip unnumbered loo 0 //借用内网loopback地址 R1(config-if)#no sh R1(config-if)#end R1# R2#conf t Enter configuration commands, one per line. End with CNTL/Z. R2(config)#int loo 0 R2(config-if)#ip add 2.2.2.2 255.255.255.0 R2(config-if)#exi R2(config)#int s 2/1 R2(config-if)#en ppp R2(config-if)#ip unn R2(config-if)#ip unnumbered l *Jul 18 14:38:00.579: %LINEPROTO-5-UPDOWN: Line protocol on interface Serial2/1, changed state to up R2(config-if)#ip unnumbered loo 0 R2(config-if)# 第三步:查看接口并测试 R1#sh run int s 2/1 Building configuration... Current configuration : 95 bytes ! interface Serial2/1 ip unnumbered Loopback0 encapsulation ppp serial restart-delay 0 end R2#sh run int s 2/1 Building configuration... Current configuration : 95 bytes ! interface Serial2/1 ip unnumbered Loopback0 encapsulation ppp serial restart-delay 0 end R1#sh ip int b Interface IP-Address OK? Method Status Protocol FastEthernet0/0 unassigned YES unset administratively down down Serial2/0 unassigned YES unset administratively down down Serial2/1 1.1.1.1 YES TFTP up up Serial2/2 unassigned YES unset administratively down down Serial2/3 unassigned YES unset administratively down down Serial3/0 unassigned YES unset administratively down down Serial3/1 unassigned YES unset administratively down down Serial3/2 unassigned YES unset administratively down down Serial3/3 unassigned YES unset administratively down down Loopback0 1.1.1.1 YES manual up up //可以看出串口地址借用的是内网loopback地址 第四步:ping测试R1 R2之间的连通性 R1#ping 2.2.2.2 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 2.2.2.2, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 40/72/116 ms //连通性正常 IP unnumbered配置 一般而言,每个逻辑接口都要配置一个独立的IP,然而IOS是支持在串行接口(点到点)配置IP unnumbered 命令,这个命令的作用可以使串行接口,“借用”另外一个接口的IP,作用是节省IP地址分配,在实际中,见于拨号网络的接入设备,因访问服务器同时给很多个用户拨入,如果每个用户对应的接口都要IP地址的话,配置管理任务较多,而且需耗费较多IP地址。 R2 (config)#interface loopback 0 R2 (config-if)#ip address 2.2.2.2 255.255.255.0 R2 (config-if)#no shut R2 (config-if)#interface serial 1 R2 (config-if)#ip unnumbered loopback 0 R1(config)#interface loopback 0 R1(config-if)#ip add R1(config-if)#ip address 1.1.1.1 255.255.255.0 R1(config-if)#interface serial 1 R1(config-if)#ip unnumbered loopback 0 R1(config-if)#clock rate 64000 以上配置已经使R1和R2连接同步串行接口借用了各自环回口IP地址,注意,以太网接口时无法借用IP的: R1(config)#interface ethernet 0 R1(config-if)#ip unnumbered loopback 0 Point-to-point (non-multi-access) interfaces only 在这种配置下,可以查看接口IP情况如下: Serial1 is up, line protocol is up Hardware is HD64570 Interface is unnumbered. Using address of Loopback0 (1.1.1.1) R2#show interfaces serial 1 Serial1 is up, line protocol is up Hardware is HD64570 Interface is unnumbered. Using address of Loopback0 (2.2.2.2) 接下来,我们验证在,无编号(ip unnumbered)接口运行路由协议的情况: (1)RIP R1(config)#router rip R1(config-router)#network 1.0.0.0 R2#show ip route Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2