Configuring a Layer 3 Switch to Work with a Router for Internet Access

Configuration Roadmap

The configuration roadmap is as follows:

1. Configure the switch as the gateway of users to allow users to communicate across network segments through VLANIF interfaces.

2. Configure the switch as the DHCP server to assign IP addresses to users.

3. Configure the NAT function on the router to enable intranet users to access the Internet.

Procedure

1. Configure the switch.

   # Configure the interfaces connected to users and corresponding VLANIF interfaces.

<Quidway> system-view

[Quidway] sysname Switch

[Switch] vlan batch 2 3

[Switch] interface gigabitethernet 0/0/2

[Switch-GigabitEthernet0/0/2] port link-type access //Set the link type of the interface to access.

[Switch-GigabitEthernet0/0/2] port default vlan 2 //Add the interface to VLAN 2.

[Switch-GigabitEthernet0/0/2] quit [Switch] interface gigabitethernet 0/0/3

[Switch-GigabitEthernet0/0/3] port link-type access

[Switch-GigabitEthernet0/0/3] port default vlan 3

[Switch-GigabitEthernet0/0/3] quit

[Switch] interface vlanif 2

[Switch-Vlanif2] ip address 192.168.1.1 24

[Switch-Vlanif2] quit [Switch] interface vlanif 3

[Switch-Vlanif3] ip address 192.168.2.1 24

[Switch-Vlanif3] quit

 

# Configure the interface connected to the router and corresponding VLANIF interface.

[Switch] vlan batch 100

[Switch] interface gigabitethernet 0/0/1

[Switch-GigabitEthernet0/0/1] port link-type access

[Switch-GigabitEthernet0/0/1] port default vlan 100

[Switch-GigabitEthernet0/0/1] quit

[Switch] interface vlanif 100

[Switch-Vlanif100] ip address 192.168.100.2 24

[Switch-Vlanif100] quit

 

# Configure the default route.

[Switch] ip route-static 0.0.0.0 0.0.0.0 192.168.100.1

 

# Configure the DHCP server.

[Switch] dhcp enable

[Switch] interface vlanif 2

[Switch-Vlanif2] dhcp select interface

[Switch-Vlanif2] dhcp server dns-list 114.114.114.114 223.5.5.5

[Switch-Vlanif2] quit

[Switch] interface vlanif 3

[Switch-Vlanif3] dhcp select interface

[Switch-Vlanif3] dhcp server dns-list 114.114.114.114 223.5.5.5

[Switch-Vlanif3] quit

 

2. Configure the router.

# Configure an IP address for the interface connected to the switch.

<Huawei> system-view

[Huawei] sysname Router

[Router] interface gigabitethernet 0/0/1

[Router-GigabitEthernet0/0/1] ip address 192.168.100.1 255.255.255.0

[Router-GigabitEthernet0/0/1] quit

 

# Configure an IP address for the interface connected to the Internet.

[Router] interface gigabitethernet 0/0/2

[Router-GigabitEthernet0/0/2] ip address 200.0.0.2 255.255.255.0

[Router-GigabitEthernet0/0/2] quit

 

# Configure a default route and a return route.

[Router] ip route-static 0.0.0.0 0.0.0.0 200.0.0.1

[Router] ip route-static 192.168.0.0 255.255.0.0 192.168.100.2

 

# Configure the NAT function to enable intranet users to access the Internet.

[Router] acl number 2001

[Router-acl-basic-2001] rule 5 permit source 192.168.0.0 0.0.255.255

[Router-acl-basic-2001] quit

[Router] interface gigabitethernet 0/0/2

[Router-GigabitEthernet0/0/2] nat outbound 2001

[Router-GigabitEthernet0/0/2] quit

 

3. Check the configuration.

Configure an IP address 192.168.1.2/24 and a gateway address 192.168.1.1 for PC1, and configure an IP address 192.168.2.2/24 and a gateway address 192.168.2.1 for PC2.

Configure an IP address 200.0.0.1/24 and a gateway address 200.0.0.2 for external network.

After the configurations are complete, PC1 and PC2 can ping the external network IP address 200.0.0.1/24 and access the Internet.

 

Configuration Files

• Switch configuration file

#

sysname Switch

#

vlan batch 2 to 3 100

#

dhcp enable

#

interface Vlanif2

   ip address 192.168.1.1 255.255.255.0

   dhcp select interface

   dhcp server dns-list 114.114.114.114 223.5.5.5

#

interface Vlanif3

   ip address 192.168.2.1 255.255.255.0

   dhcp select interface

   dhcp server dns-list 114.114.114.114 223.5.5.5

#

interface Vlanif100

   ip address 192.168.100.2 255.255.255.0

#

interface GigabitEthernet0/0/1

   port link-type access port default vlan 100

#

interface GigabitEthernet0/0/2

   port link-type access port default vlan 2

#

interface GigabitEthernet0/0/3

   port link-type access port default vlan 3

#

   ip route-static 0.0.0.0 0.0.0.0 192.168.100.1

#

return

 

• Router configuration file

#

sysname Router

#

acl number 2001

   rule 5 permit source 192.168.0.0 0.0.255.255

#

interface GigabitEthernet0/0/1

   ip address 192.168.100.1 255.255.255.0

#

interface GigabitEthernet0/0/2

   ip address 200.0.0.2 255.255.255.0

   nat outbound 2001

#

ip route-static 0.0.0.0 0.0.0.0 200.0.0.1

ip route-static 192.168.0.0 255.255.0.0 192.168.100.2

#

return