CCIE-03-Layer2-LAN-TS

实验条件

网络拓朴

Output1

Output2

实验目标

排除故障使得PC101访问Server1时符合图片中给出的Output

开始排错

根据要求，ping对方。

PC101#ping 172.16.200.200      
% Unrecognized host or address, or protocol not running.
PC101#show ip route 
Default gateway is not set

Host               Gateway           Last Use    Total Uses  Interface
ICMP redirect cache is empty

PC101#show ip int br
Interface                  IP-Address      OK? Method Status                Protocol
Ethernet0/0                unassigned      YES DHCP   up                    up      
Ethernet0/1                unassigned      YES TFTP   administratively down down    
Ethernet0/2                unassigned      YES TFTP   administratively down down    
Ethernet0/3                unassigned      YES TFTP   administratively down down 

发现没有获取到IP地址，搜索DHCP服务器

R7#show run | s dhcp 
ip dhcp pool Server2
 host 172.16.200.200 255.255.255.0
 client-identifier 01aa.bbcc.002d.00
 default-router 172.16.200.1 
 dns-server 172.7.7.7 
R7# 

R8#show run | s dhcp
ip dhcp pool HOST1
 host 172.16.100.200 255.255.255.0
 client-identifier 01aa.bbcc.0021.11
 dns-server 172.8.8.8 
R8#

根据拓扑结构确定PC101是通过R8的DHCP服务器获取到IP地址，由于PC101和我们的R8不是在相同的网络因此需要配置DHCP中继才能让PC获取到IP地址，所以还需要检查交换机上的中继配置，PC101的VLAN100，因此需要在SVI VLAN 100下检查配置，

SW2#show run interface vlan 100
Building configuration...

Current configuration : 124 bytes
!
interface Vlan100
 ip address 172.16.100.1 255.255.255.0
 ip helper-address 172.7.7.7 
end
SW2#

发现DHCP中继并没有指向172.8.8.8，因此需要把中继指向R8

问题1. SW2上的DHCP中继没有配置正确

配置上指向R8的中继

SW2#conf t
SW2(config)#int vlan 100
SW2(config-if)#ip helper-address 172.8.8.8
SW2#show run interface vlan 100
Building configuration...

Current configuration : 124 bytes
!
interface Vlan100
 ip address 172.16.100.1 255.255.255.0
 ip helper-address 172.7.7.7 
 ip helper-address 172.8.8.8 
end

配置成功，现在测试一下Vlan100到R8的172.8.8.8的网络是否连通（没有联通就肯定无法获取IP）

SW2#ping 172.8.8.8 source vlan 100
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 172.8.8.8, timeout is 2 seconds:
Packet sent with a source address of 172.16.100.100 
.....
Success rate is 0 percent (0/5)
SW2#

发现无法连接R8的环回口地址，同时检查R8和SW2的VLAN100的SVI接口信息

R8#show ip int br          
Interface                  IP-Address      OK? Method Status                Protocol
Ethernet0/0                unassigned      YES TFTP   up                    up      
Ethernet0/0.123            123.45.67.26    YES TFTP   up                    up      
Ethernet0/0.124            124.45.67.26    YES TFTP   up                    up      
Ethernet0/0.125            125.45.67.26    YES TFTP   up                    up      
Ethernet0/1                172.16.1.17     YES TFTP   up                    up      
Ethernet0/2                172.16.1.6      YES TFTP   up                    up      
Ethernet0/3                172.16.1.13     YES TFTP   up                    up      
Loopback0                  172.8.8.8       YES TFTP   up                    up      
R8#show run interface lo0
Building configuration...

Current configuration :