Troubleshooting guide

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 aren't familiar with configuring Cisco devices and would like to follow a step−by−step
configuration, click here.
Cisco DSL Router with Static IP Address and NAT
!−−− Comments contain explanations and additional information.
service timestamps debug datetime msec
service timestamps log datetime msec
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
no ip address
no ip directed−broadcast
no atm ilmi−keepalive
!
interface atm0.1 point−to−point
ip address <ip address> <subnet mask>
ip nat outside
pvc <vpi/vci>
encapsulation aal5snap
!−−− Common PVC values supported by ISPs are 0/35 or 8/35.
!−−− Confirm your PVC values with your ISP.
!
!
ip nat inside source list 1 interface atm0.1 overload
!−−− If you have a pool (a range) of public IP addresses provided
!−−− by your ISP, you can use a NAT Pool. Replace
!−−− ip nat inside source list 1 interface atm0.1 overload
!−−− with the following two configuration statements:
!−−− ip nat inside source list 1 pool <nat pool name> overload
!−−− ip nat pool <nat pool name> <first ip address> <last ip address>
!−−− netmask <subnet mask>
!−−− If Internet users require access to an internal server, you can
!−−− add the following static NAT configuration statement:
!−−− ip nat inside source static tcp <inside ip address of server> {80 or 25}
!−−− <outside well−known ip address of server> {80 or 25} extendable
!−−− Note: TCP port 80 (HTTP/web) and TCP port 25 (SMTP/mail) are used
Cisco DSL Router Configuration and Troubleshooting Guide