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Chapter 4      Configuring PPP over ATM with NAT
  Configuration Example
NoteIf you want to use NAT with a virtual-template interface, you must configure a loopback interface. See 
Chapter 1, “Basic Router Configuration,” for information on configuring the loopback interface.
For complete information on NAT commands, see the Cisco IOS Release 12.3 documentation set. For 
more general information on NAT...

 
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Chapter 4      Configuring PPP over ATM with NAT
  Configuration Example
interface Dialer0 ip address negotiated
 ip mtu 1492
 encapsulation ppp dialer pool 1
 dialer-group 1
 ppp authentication chap!
ip classless (default)
!ip nat pool pool1 192.168.1.0 192.168.2.0 netmask 0.0.0.255
ip nat inside source list 1 interface Dialer0 overload
!access-list 1 permit 192.168.1.0 0.0.0.255
dialer-list 1 protocol...

CH A P T E R
 
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5
Configuring a LAN with DHCP and VLANs
The Cisco 870 series routers support clients on both physical LANs and virtual LANs (VLANs). The 
routers can use the Dynamic Host Configuration Protoc ol (DHCP) to enable automatic assignment of IP 
configurations for nodes on these networks.
Figure 5-1  shows a typical deployment scenario with tw o physical LANs connected by the router and 
two VLANs....

 
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Chapter 5      Configuring a LAN with DHCP and VLANs
  Configure DHCP
When you configure a DHCP server, you must configure the server properties, policies, and DHCP 
options. 
NoteWhenever you change server properties, you must reload the server with the configuration data from the 
Network Registrar database.
VLANs
The Cisco 870 series access routers support four Fast Ethernet ports on which you can...

 
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Chapter 5      Configuring a LAN with DHCP and VLANs
  Configure DHCP
Step 3ip dhcp excluded-address low-address 
[high-address] 
Example:
Router(config)# ip dhcp excluded-address 
192.168.9.0
Specifies IP addresses that the DHCP server should 
not assign to DHCP clients. In this example, we are 
excluding the router address.
Step 4ip dhcp pool name
Example:
Router(config)# ip dhcp pool dpool1...

 
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Chapter 5      Configuring a LAN with DHCP and VLANs
  Configure DHCP
Configuration Example
The following configuration example shows a portion of the configuration file for the DCHP 
configuration described in this chapter.
ip dhcp excluded-address 192.168.9.0
!ip dhcp pool dpool1
   import all
   network 10.10.0.0 255.255.255.0   default-router 10.10.10.10
   dns-server 192.168.35.2
   domain-name...

 
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Chapter 5      Configuring a LAN with DHCP and VLANs   Configure VLANs
Router# show ip dhcp server statistics
Memory usage         15419
Address pools        1Database agents      0
Automatic bindings   0
Manual bindings      0Expired bindings     0
Malformed messages   0
Secure arp entries   0
Message              Received
BOOTREQUEST          0DHCPDISCOVER         0
DHCPREQUEST          0
DHCPDECLINE...

 
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Chapter 5      Configuring a LAN with DHCP and VLANs
  Configure VLANs
Verify Your VLAN Configuration
Use the following commands to view your VLAN configuration.
 show—Entered from VLAN database mode. Displays summary configuration information for all 
configured VLANs.
 show vlan-switch—Entered from privileged EXEC mode. Displays detailed configuration 
information for all configured VLANs. 

 
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Chapter 5      Configuring a LAN with DHCP and VLANs
  Configure VLANs
Router# vlan databaseRouter(vlan)# show
  VLAN ISL Id: 1
    Name: default    Media Type: Ethernet
    VLAN 802.10 Id: 100001
    State: Operational    MTU: 1500
    Translational Bridged VLAN: 1002
    Translational Bridged VLAN: 1003
  VLAN ISL Id: 1002
    Name: fddi-default    Media Type: FDDI
    VLAN 802.10 Id: 101002
    State:...

 
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Chapter 5      Configuring a LAN with DHCP and VLANs
  Configure VLANs
Router# show vlan-switch
VLAN Name                             Status    Ports
---- -------------------------------- --------- -------------------------------1    default                          active    Fa0, Fa1, Fa2, Fa3
1002 fddi-default                     active
1003 token-ring-default               active1004 fddinet-default...