网络应用当中出现的故障问题，总是让我们应接不暇。那么这次我们就来讲解一下IP协议故障处理：接口下没有借用到地址的相关问题。那么还是老样子，看一下网络结构吧。
IP协议故障处理：网络环境
在某次测试过程中，配置接口借用其他接口的IP地址，组网图如下。
图 IP地址借用案例组网图
配置后发现RouterA的POS2/0/0接口无法借用GE1/0/0的IP地址。
IP协议故障处理：故障分析
查看POS2/0/0接口是否配置了地址借用，在接口视图下执行display this命令收集信息，得到显示信息如下。
[RouterA-Pos2/0/0] display this#interface Pos2/0/0 link-protocol pppip address unnumbered interface GigabitEthernet1/0/0#return查看GE1/0/0接口是否配置了IP地址，在接口视图下执行display this interface命令收集信息，得到显示信息如下。
- <RouterA-GigabitEtherent1/0/0> display this interfaceGigabitEthernet1/0/0 current state : UP
- Line protocol current state : DOWNDescription : To beijingRoute Port,The Maximum Transmit Unit is 1500Internet protocol processing : disabled
- IP Sending Frames' Format is PKTFMT_ETHNT_2, Hardware address is 00e0-fc7d-a497
- The Vendor PN is HFBR-5710L
- Port BW: 1G, Transceiver max BW: 1G, Transceiver Mode: MultiMode
- WaveLength: 850nm, Transmission Distance: 550m
- Loopback:none, full-duplex mode, negotiation: disable, Pause Flowcontrol:Receive
- Enable and Send Enable
- Last physical up time : 2008-08-19 09:08:54
- Last physical down time : 2008-08-19 09:08:38
- Statistics last cleared:never
- Last 300 seconds input rate: 208 bits/sec, 0 packets/sec
- Last 300 seconds output rate: 200 bits/sec, 0 packets/sec
- Input: 218807 bytes, 2299 packets
- Output: 212849 bytes, 2237 packets
- Input:
- Unicast: 1429 packets, Multicast: 867 packets
- Broadcast: 3 packets, JumboOctets: 0 packets
- CRC: 0 packets, Symbol: 0 packets
- Overrun: 0 packets
- InRangeLength: 0 packets
- LongPacket: 0 packets, Jabber: 0 packets, Alignment: 0 packets
- Fragment: 0 packets, Undersized Frame: 0 packets
- RxPause: 0 packets
- Output:
- Unicast: 1430 packets, Multicast: 803 packets
- Broadcast: 4 packets, JumboOctets: 0 packets
- Lost: 0 packets, Overflow: 0 packets, Underrun: 0 packets
- TxPause: 0 packets通过显示信息发现问题原因，RouterA的GE1/0/0接口没有配置IP地址。
IP协议故障处理：操作步骤
1.在RouterA上执行命令system-view，进入系统视图。
2.执行命令interface gigabitethernet 1/0/0，进入GE接口视图。
3.执行命令ip address 172.16.10.1 24，设置IP地址。
执行完上述操作，可以发现RouterA的接口POS2/0/0可以借用接口GE1/0/0的IP地址了。
IP协议故障处理：案例总结
当配置地址借用时首先保证被借用的接口已经正确配置了IP地址。
