Cisco Router 800 Series Software Configuration Guide

 
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Chapter 4      Network Scenarios
Configuring the DHCP Server
In this scenario, the small business or remote user on the Ethernet LAN can 
connect to the Internet through ADSL. The Ethernet interface carries the data 
packet through the LAN and offloads it to the RFC 1483 connection on the ATM 
interface. The number of ATM PVCs is set by default.
NAT (represented as the dashed line at the edge of the 827 routers) signifies two 
addressing...

 
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Configuring the DHCP Server
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Configuring the ATM Interface
Use this table to configure the ATM interface, beginning in global configuration 
mode.
Configuring NAT
Complete the follow steps to configure NAT, beginning in global configuration 
mode. Command Task
Step 1interface ethernet 0Enter configuration mode for the Ethernet 
interface.
Step 2ip address 192.168.1.1 255.255.255.0Set the IP address and subnet...

 
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Chapter 4      Network Scenarios
Configuring the DHCP Server
Configuration Examples
In the following configuration examples, you do not have to enter the commands 
marked “default.” These commands appear automatically in the configuration file 
that is generated when you use the show running-config command.
The following example shows an RFC 1483 LLC/SNAP encapsulation over 
AT M .  
!
interface Ethernet0
ip address 192.168.1.1...

 
Chapter 4      Network Scenarios
Configuring the DHCP Server
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78-5372-06 ip address 200.200.100.1 255.255.255.0
no ip directed-broadcast (default)
ip nat outside
no atm ilmi-keepalive (default)
pvc 8/35 
 encapsulation aal5snap
protocol ip 200.200.100.254 broadcast
!
bundle-enable
!
ip nat inside source list 1 interface ATM0 overload
ip classless (default)
ip route 0.0.0.0 0.0.0.0 200.200.100.254
!
access-list 1 permit 192.168.1.0 0.0.0.255
!...

 
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Configuring the DHCP Server
Integrated Routing and Bridging 
This network shows a user connecting to the Internet using integrated routing and 
bridging (IRB) to use NAT across a bridged interface. This scenario might work 
for you if you want to add functionality to an endpoint router without 
reconfiguring the central site. For example, you can provide an IP address and 
NAT in a bridged network without...

 
Chapter 4      Network Scenarios
Configuring the DHCP Server
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One side of the network (the WAN, in this scenario) is configured to act as a 
bridge. The Bridge-Group Virtual Interface (BVI) is configured to act as a routed 
interface from the WAN bridge-group to the nonbridged LAN interface. From the 
LAN, the network appears as a router. From the WAN, the network appears as a 
bridge.
The ATM interface uses AAL5SNAP encapsulation. The number...

 
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Configuring the DHCP Server
Configuring the ATM Interface
Follow the steps below to configure the ATM interface, beginning in global 
configuration mode. Command Task
Step 1bridge irbSpecify IRB.
Step 2bridge 1 route ipEnable IP routing to and from bridge-group 1.
Step 3bridge 1 protocol ieeeSpecify the bridge protocol to define the type 
of Spanning-Tree Protocol (STP).
Step 4interface ethernet 0Enter...

 
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Configuring the DHCP Server
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Configuring the BVI
Follow the steps below to configure the BVI, beginning in global configuration 
mode.
Configuring NAT
Follow the steps below to configure NAT, beginning in global configuration 
mode. Command Task
Step 1interface bvi 1Enter configuration mode for the BVI.
Step 2ip address 200.200.100.1 255.255.255.0Set the IP address and subnet mask for the 
BVI.
Step 3exitExit...

 
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Chapter 4      Network Scenarios
Configuring the DHCP Server
Configuration Example
In the following configuration example, you do not have to enter the commands 
marked “default.” These commands appear automatically in the configuration file 
that is generated when you use the show running-config command.
bridge irb
!
interface Ethernet0
ip address 192.168.1.1 255.255.255.0
no ip directed-broadcast (default)
ip nat inside
!
interface ATM0
no...

 
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Configuring the DHCP Server
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78-5372-06 no ip directed-broadcast (default)
ip nat outside
!
ip nat pool test 200.200.100.1 200.200.100.1 netmask 255.255.255.0
ip nat inside source list 101 pool test overload
ip classless (default)
!
bridge 1 protocol ieee
bridge 1 route ip
!
access-list 101 permit ip 192.168.1.0 0.0.0.255 any log
!
ip route 0.0.0.0 0.0.0.0 200.200.100.254 (default gateway)
!
end
Concurrent Routing and...