学员提问：
登陆交换机发现下面这个错误
04:29:29: %CDP-4-NATIVE_VLAN_MISMATCH: Native VLAN mismatch discovered on Gigabi
tEthernet0/20 (80), with Switch FastEthernet0/24 (1).
04:30:29: %CDP-4-NATIVE_VLAN_MISMATCH: Native VLAN mismatch discovered on Gigabi
tEthernet0/20 (80), with Switch FastEthernet0/24 (1).
不能上外网,下面是配置文件，这是什么问题？
Switch#show run
Building configuration...
04:09:29: %CDP-4-NATIVE_VLAN_MISMATCH: Native VLAN mismatch discovered on Gigabi
tEthernet0/20 (80), with Switch FastEthernet0/24 (1).
Current configuration : 3702 bytes
!
version 12.2
no service pad
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname Switch
!
enable password xindu
!
no aaa new-model
system mtu routing 1500
ip subnet-zero
ip routing
!
!
!
no file verify auto
spanning-tree mode pvst
spanning-tree extend system-id
!
vlan internal allocation policy ascending
!
!
interface GigabitEthernet0/1
spanning-tree portfast
!
interface GigabitEthernet0/2
switchport access vlan 20
spanning-tree portfast
!
interface GigabitEthernet0/3
switchport access vlan 30
spanning-tree portfast
!
interface GigabitEthernet0/4
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet0/5
switchport access vlan 80
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet0/6
switchport access vlan 80
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet0/7
switchport access vlan 80
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet0/8
switchport access vlan 80
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet0/9
switchport access vlan 80
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet0/10
switchport access vlan 80
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet0/11
switchport access vlan 80
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet0/12
switchport access vlan 80
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet0/13
switchport access vlan 80
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet0/14
switchport access vlan 80
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet0/15
switchport access vlan 80
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet0/16
switchport access vlan 80
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet0/17
switchport access vlan 80
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet0/18
switchport access vlan 80
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet0/19
switchport access vlan 80
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet0/20
switchport access vlan 80
switchport trunk native vlan 80
switchport mode access
!
interface GigabitEthernet0/21
switchport access vlan 80
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet0/22
switchport access vlan 80
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet0/23
!
interface GigabitEthernet0/24
no switchport
ip address 1.1.1.22 255.255.255.252
!
interface GigabitEthernet0/25
!
interface GigabitEthernet0/26
!
interface GigabitEthernet0/27
!
interface GigabitEthernet0/28
!
interface Vlan1
no ip address
!
interface Vlan20
ip address 192.168.2.1 255.255.255.0
!
interface Vlan24
no ip address
!
interface Vlan26
no ip address
!
interface Vlan30
ip address 192.168.3.1 255.255.255.0
!
interface Vlan40
ip address 192.168.4.1 255.255.255.0
!
interface Vlan50
ip address 192.168.5.1 255.255.255.0
!
interface Vlan60
ip address 192.168.6.1 255.255.255.0
!
interface Vlan70
no ip address
!
interface Vlan80
ip address 192.168.60.1 255.255.255.0
!
ip classless
ip route 0.0.0.0 0.0.0.0 1.1.1.21
ip http server
ip http secure-server
!
!
!
control-plane
!
!
line con 0
line vty 0
password xindu
login
line vty 1 4
login
line vty 5 15
login
!
end
捷盈讲师及学员解答：
看一下20端口连接设备的配置。注意两端配置VLAN要一致，一般上述错误可以不理。no cdp adv用这个关掉也行。