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TOPIC: Cisco 871 and DHCP on external interface problems

Cisco 871 and DHCP on external interface problems 10 years 1 week ago #30064

I have configured the router to use dhcp on the f4 interface, which is the external interface. I can never get out to the internet though. The clients get ip addresses, and they can ping the router, but no where past that. The router also cannot ping anywhere on the internat. I am using a cable modem, not sure if I should have a crossover cable between the cable modem and the router or a straight cable. I tried both and could not get it to work.

I am not even sure that I am getting an ip address on the external interface. If I hook up my Dlink router that is set for dhcp for the external ip address, it gets one just fine. Not even sure how to tell that on the cisco 871 router.

Here is my router config if anyone has any ideas why I would not be able to get to the internet from the router, or client computers.


service password-encryption
hostname TelrexR1
enable secret XXXXXXX
enable password XXXXXXX
aaa new-model
aaa authentication login default local
aaa authorization exec default local
aaa session-id common
ip http server
ip http secure-server
line con 0
password XXXXXXXX
line vty 0 4
password XXXXXXXX
ip domain name
no ip domain lookup
ip dns server
username xxxxxxx privilege 15 password xxxxxxx
ip dhcp excluded-address
service dhcp
interface Vlan1
ip address
description Internal Network
ip nat inside
ip virtual-reassembly
ip dhcp pool vlan1
import all
lease 4
interface f4
ip address dhcp
ip nat outside
ip virtual-reassembly
interface FastEthernet0
switchport access vlan 1
no shut
interface FastEthernet1
switchport access vlan 1
no shut
interface FastEthernet2
switchport access vlan 1
no shut
interface FastEthernet3
switchport access vlan 1
no shut
ip nat inside source list 100 interface fastethernet4 overload
access-list 100 permit ip any
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