因此，为了简单起见，在测试此配置时，我有一个示例项目，如下所示： 故障：

配置

在也是 vtp 服务器的多层交换机上配置的 vlan：

局域网2：

ip地址192.168.2.1 255.255.255.0

ip 助手地址 192.168.3.1

局域网 3：

• ip地址192.168.3.2 255.255.255.0

dhcp驻留在vlan 3，静态地址192.168.3.1

水池：

• 默认网关：192.168.3.254

• 起始IP：192.168.3.2

• 子网掩码：255.255.255.0

• 最大用户数：200

所有交叉连接都是中继（已验证）

所有直接连接都分配给 vlan 3（已验证）

pc 1 & 2 可以正常接收来自 DHCP 服务器的响应，但 PC0 不能。

我试图在尝试调试我正在为我的网络 101 类工作的 3 层网络设计时让它工作。经过多天试图找出流量路由不正确的原因后，我打破了设计，试图找到故障点。据我缩小范围，问题出在中间交换机（交换机 1），它是分布层的一部分，但我无法掌握它的配置有什么问题（所有端口中继，vtp 模式透明）。

我觉得我在路由设置中错过了一些非常基本的东西，特别是当我过去让这个配置工作时，但我无法复制正确的配置。

//
//multilayer switch0
//
Building configuration...

Current configuration : 2249 bytes
!
version 12.2
no service timestamps log datetime msec
no service timestamps debug datetime msec
no service password-encryption
!
hostname Switch
!
!
!
!
!
!
!
ip routing
!
!
!
!
!
!
!
!
!
!
!
!
!
!
spanning-tree mode pvst
!
!
!
!
!
!
interface FastEthernet0/1
 switchport trunk encapsulation dot1q
!
interface FastEthernet0/2
 switchport trunk encapsulation dot1q
!
interface FastEthernet0/3
 switchport trunk encapsulation dot1q
!
interface FastEthernet0/4
 switchport trunk encapsulation dot1q
!
interface FastEthernet0/5
 switchport trunk encapsulation dot1q
!
interface FastEthernet0/6
 switchport trunk encapsulation dot1q
!
interface FastEthernet0/7
 switchport trunk encapsulation dot1q
!
interface FastEthernet0/8
 switchport trunk encapsulation dot1q
!
interface FastEthernet0/9
 switchport trunk encapsulation dot1q
!
interface FastEthernet0/10
 switchport trunk encapsulation dot1q
!
interface FastEthernet0/11
 switchport trunk encapsulation dot1q
!
interface FastEthernet0/12
 switchport trunk encapsulation dot1q
!
interface FastEthernet0/13
 switchport trunk encapsulation dot1q
!
interface FastEthernet0/14
 switchport trunk encapsulation dot1q
!
interface FastEthernet0/15
 switchport trunk encapsulation dot1q
!
interface FastEthernet0/16
 switchport trunk encapsulation dot1q
!
interface FastEthernet0/17
 switchport trunk encapsulation dot1q
!
interface FastEthernet0/18
 switchport trunk encapsulation dot1q
!
interface FastEthernet0/19
 switchport trunk encapsulation dot1q
!
interface FastEthernet0/20
 switchport trunk encapsulation dot1q
!
interface FastEthernet0/21
 switchport trunk encapsulation dot1q
!
interface FastEthernet0/22
 switchport trunk encapsulation dot1q
!
interface FastEthernet0/23
 switchport trunk encapsulation dot1q
!
interface FastEthernet0/24
 switchport trunk encapsulation dot1q
!
interface GigabitEthernet0/1
!
interface GigabitEthernet0/2
!
interface Vlan1
 no ip address
 shutdown
!
interface Vlan2
 mac-address 0010.1151.c701
 ip address 192.168.2.1 255.255.255.0
 ip helper-address 192.168.3.1
!
interface Vlan3
 mac-address 0010.1151.c702
 ip address 192.168.3.254 255.255.255.0
!
ip classless
!
ip flow-export version 9
!
!
!
!
!
!
!
line con 0
!
line aux 0
!
line vty 0 4
 login
!
!
!
end


//
//switch 0
//
Switch#sh running-config
Building configuration...

Current configuration : 2168 bytes
!
version 12.2
no service timestamps log datetime msec
no service timestamps debug datetime msec
no service password-encryption
!
hostname Switch
!
!
!
!
!
spanning-tree mode pvst
!
interface FastEthernet0/1
 switchport access vlan 3
 switchport mode access
!
interface FastEthernet0/2
 switchport access vlan 3
 switchport mode access
!
interface FastEthernet0/3
 switchport access vlan 3
 switchport mode access
!
interface FastEthernet0/4
 switchport access vlan 3
 switchport mode access
!
interface FastEthernet0/5
 switchport access vlan 3
 switchport mode access
!
interface FastEthernet0/6
 switchport access vlan 3
 switchport mode access
!
interface FastEthernet0/7
 switchport access vlan 3
 switchport mode access
!
interface FastEthernet0/8
 switchport access vlan 3
 switchport mode access
!
interface FastEthernet0/9
 switchport access vlan 3
 switchport mode access
!
interface FastEthernet0/10
 switchport access vlan 3
 switchport mode access
!
interface FastEthernet0/11
 switchport access vlan 3
 switchport mode access
!
interface FastEthernet0/12
 switchport access vlan 3
 switchport mode access
!
interface FastEthernet0/13
 switchport access vlan 3
 switchport mode access
!
interface FastEthernet0/14
 switchport access vlan 3
 switchport mode access
!
interface FastEthernet0/15
 switchport access vlan 3
 switchport mode access
!
interface FastEthernet0/16
 switchport access vlan 3
 switchport mode access
!
interface FastEthernet0/17
 switchport access vlan 3
 switchport mode access
!
interface FastEthernet0/18
 switchport access vlan 3
 switchport mode access
!
interface FastEthernet0/19
 switchport access vlan 3
 switchport mode access
!
interface FastEthernet0/20
 switchport access vlan 3
 switchport mode access
!
interface FastEthernet0/21
 switchport access vlan 3
 switchport mode access
!
interface FastEthernet0/22
 switchport access vlan 3
 switchport mode access
!
interface FastEthernet0/23
!
interface FastEthernet0/24
 switchport mode trunk
!
interface GigabitEthernet0/1
!
interface GigabitEthernet0/2
!
interface Vlan1
 no ip address
 shutdown
!
!
!
!
line con 0
!
line vty 0 4
 login
line vty 5 15
 login
!
!
!
end

//
//switch1
//
Building configuration...

Current configuration : 1620 bytes
!
version 12.2
no service timestamps log datetime msec
no service timestamps debug datetime msec
no service password-encryption
!
hostname Switch
!
!
!
!
vtp mode transparent
!
!
spanning-tree mode pvst
!
interface FastEthernet0/1
 switchport mode trunk
!
interface FastEthernet0/2
 switchport mode trunk
!
interface FastEthernet0/3
 switchport mode trunk
!
interface FastEthernet0/4
 switchport mode trunk
!
interface FastEthernet0/5
 switchport mode trunk
!
interface FastEthernet0/6
 switchport mode trunk
!
interface FastEthernet0/7
 switchport mode trunk
!
interface FastEthernet0/8
 switchport mode trunk
!
interface FastEthernet0/9
 switchport mode trunk
!
interface FastEthernet0/10
 switchport mode trunk
!
interface FastEthernet0/11
 switchport mode trunk
!
interface FastEthernet0/12
 switchport mode trunk
!
interface FastEthernet0/13
 switchport mode trunk
!
interface FastEthernet0/14
 switchport mode trunk
!
interface FastEthernet0/15
 switchport mode trunk
!
interface FastEthernet0/16
 switchport mode trunk
!
interface FastEthernet0/17
 switchport mode trunk
!
interface FastEthernet0/18
 switchport mode trunk
!
interface FastEthernet0/19
 switchport mode trunk
!
interface FastEthernet0/20
 switchport mode trunk
!
interface FastEthernet0/21
 switchport mode trunk
!
interface FastEthernet0/22
 switchport mode trunk
!
interface FastEthernet0/23
 switchport mode trunk
!
interface FastEthernet0/24
 switchport mode trunk
!
interface GigabitEthernet0/1
!
interface GigabitEthernet0/2
!
interface Vlan1
 no ip address
 shutdown
!
!
!
!
line con 0
!
line vty 0 4
 login
line vty 5 15
 login
!
!
!
end

//
// switch 2
//
Building configuration...

Current configuration : 2168 bytes
!
version 12.2
no service timestamps log datetime msec
no service timestamps debug datetime msec
no service password-encryption
!
hostname Switch
!
!
!
!
!
spanning-tree mode pvst
!
interface FastEthernet0/1
 switchport access vlan 3
 switchport mode access
!
interface FastEthernet0/2
 switchport access vlan 2
 switchport mode access
!
interface FastEthernet0/3
 switchport access vlan 2
 switchport mode access
!
interface FastEthernet0/4
 switchport access vlan 2
 switchport mode access
!
interface FastEthernet0/5
 switchport access vlan 2
 switchport mode access
!
interface FastEthernet0/6
 switchport access vlan 2
 switchport mode access
!
interface FastEthernet0/7
 switchport access vlan 2
 switchport mode access
!
interface FastEthernet0/8
 switchport access vlan 2
 switchport mode access
!
interface FastEthernet0/9
 switchport access vlan 2
 switchport mode access
!
interface FastEthernet0/10
 switchport access vlan 2
 switchport mode access
!
interface FastEthernet0/11
 switchport access vlan 2
 switchport mode access
!
interface FastEthernet0/12
 switchport access vlan 2
 switchport mode access
!
interface FastEthernet0/13
 switchport access vlan 2
 switchport mode access
!
interface FastEthernet0/14
 switchport access vlan 2
 switchport mode access
!
interface FastEthernet0/15
 switchport access vlan 2
 switchport mode access
!
interface FastEthernet0/16
 switchport access vlan 2
 switchport mode access
!
interface FastEthernet0/17
 switchport access vlan 2
 switchport mode access
!
interface FastEthernet0/18
 switchport access vlan 2
 switchport mode access
!
interface FastEthernet0/19
 switchport access vlan 2
 switchport mode access
!
interface FastEthernet0/20
 switchport access vlan 2
 switchport mode access
!
interface FastEthernet0/21
 switchport access vlan 2
 switchport mode access
!
interface FastEthernet0/22
 switchport access vlan 2
 switchport mode access
!
interface FastEthernet0/23
!
interface FastEthernet0/24
 switchport mode trunk
!
interface GigabitEthernet0/1
!
interface GigabitEthernet0/2
!
interface Vlan1
 no ip address
 shutdown
!
!
!
!
line con 0
!
line vty 0 4
 login
line vty 5 15
 login
!
!
!
end

//
// switch 3
//
Building configuration...

Current configuration : 1118 bytes
!
version 12.2
no service timestamps log datetime msec
no service timestamps debug datetime msec
no service password-encryption
!
hostname Switch
!
!
!
!
!
spanning-tree mode pvst
!
interface FastEthernet0/1
 switchport access vlan 3
 switchport mode access
!
interface FastEthernet0/2
!
interface FastEthernet0/3
!
interface FastEthernet0/4
!
interface FastEthernet0/5
!
interface FastEthernet0/6
!
interface FastEthernet0/7
!
interface FastEthernet0/8
!
interface FastEthernet0/9
!
interface FastEthernet0/10
!
interface FastEthernet0/11
!
interface FastEthernet0/12
!
interface FastEthernet0/13
!
interface FastEthernet0/14
!
interface FastEthernet0/15
!
interface FastEthernet0/16
!
interface FastEthernet0/17
!
interface FastEthernet0/18
!
interface FastEthernet0/19
!
interface FastEthernet0/20
!
interface FastEthernet0/21
!
interface FastEthernet0/22
!
interface FastEthernet0/23
!
interface FastEthernet0/24
 switchport mode trunk
!
interface GigabitEthernet0/1
!
interface GigabitEthernet0/2
!
interface Vlan1
 no ip address
 shutdown
!
!
!
!
line con 0
!
line vty 0 4
 login
line vty 5 15
 login
!
!
!
end