Troubleshooting guide

Network Address Translation (NAT).
Design an IP addressing scheme for your private LAN.•
Configure an IP address and subnet mask on the Cisco DSL Router Ethernet interface.•
Configure the ATM interface (Asymetric Digital Subscriber Line (ADSL) interface) of the Cisco DSL
Router with an ATM permanent virtual circuit (PVC) and encapsulation.
•
Enable integrated routing and bridging (IRB).•
Create and configure the Bridge Group Virtual Interface (BVI) interface of the Cisco DSL Router for
IRB with a negotiated IP address.
•
Configure NAT on the Cisco DSL Router to allow sharing of the dynamic public IP address of the
BVI interface.
•
Optional: NAT Pool, if additional IP addresses have been provided by your ISP.♦
Optional: Static NAT, if Internet users require access to internal servers.♦
Configure each host PC with an IP address, subnet mask, default gateway, and Domain Name System
(DNS) server(s).
Alternatively, if you want the Cisco DSL Router to assign your PC clients' dynamic IP addresses,
configure each PC to obtain an IP address and DNS server(s) automatically via DHCP.
•
Configuration
Tip: If you are not familiar with configuring Cisco devices and would like to follow a step−by−step
configuration, click here.
Cisco DSL Router with a Dynamic IP Address
!−−− Comments contain explanations and additional information.
service timestamps debug datetime msec
service timestamps log datetime msec
!
bridge irb
!
ip subnet−zero
!
ip dhcp excluded−address <ip address of ethernet0>
ip dhcp pool <dhcp pool name>
network <ip network address of ethernet0> <subnet mask>
default−router <ip address of ethernet0>
dns−server <ip address of dns server>
!
interface ethernet0
no shut
ip address <ip address> <subnet mask>
ip nat inside
no ip directed−broadcast
!
interface atm0
no shut
Cisco DSL Router Configuration and Troubleshooting Guide