Showing results for 
Search instead for 
Did you mean: 

cable modem and cisco 2600



I'm trying to configure a cisco router 2600, my internet connection is via a cable modem. I get a dynamic IP from the cable modem but when I ping to any external IP I have errors.Copy show config and show interface f0/1

GUEST#show config

Using 1103 out of 29688 bytes


version 12.2

service timestamps debug uptime

service timestamps log uptime

no service password-encryption


hostname GUEST


enable secret 5 $1$JK3y$ns4oiH0tN0XAPk8G7JOwS/

enable password 123456789


ip subnet-zero



ip name-server dns provider1

ip name-server dns provider2

ip dhcp excluded-address


ip dhcp pool LAN-INTERNA


   dns-server dns provider1 dns provider2



call rsvp-sync



interface FastEthernet0/0

description LAN-INTERNA

ip address

ip nat inside

no ip mroute-cache

speed auto


no mop enabled


interface FastEthernet0/1

description INTERNET

ip address dhcp

ip nat outside

no ip mroute-cache

duplex auto

speed auto


ip nat inside source list 100 interface FastEthernet0/1 overload

ip classless

ip route FastEthernet0/1

no ip http server


access-list 100 permit ip any any



dial-peer cor custom






line con 0

line aux 0

line vty 0 4

password 123456789




GUEST#show interface f0/1

FastEthernet0/1 is up, line protocol is up

  Hardware is AmdFE, address is 0005.5e63.77c1 (bia 0005.5e63.77c1)

  Description: INTERNET

  Internet address is a.b.c.d/24

  MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,

     reliability 255/255, txload 1/255, rxload 1/255

  Encapsulation ARPA, loopback not set

  Keepalive set (10 sec)

  Full-duplex, 100Mb/s, 100BaseTX/FX

  ARP type: ARPA, ARP Timeout 04:00:00

  Last input 00:00:00, output 00:00:02, output hang never

  Last clearing of "show interface" counters never

  Input queue: 2/75/556/0 (size/max/drops/flushes); Total output drops: 0

  Queueing strategy: fifo

  Output queue: 0/40 (size/max)

  5 minute input rate 26000 bits/sec, 41 packets/sec

  5 minute output rate 0 bits/sec, 0 packets/sec

     10632 packets input, 666156 bytes

     Received 10632 broadcasts, 0 runts, 0 giants, 0 throttles

     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored

     0 watchdog

     0 input packets with dribble condition detected

     45 packets output, 5319 bytes, 0 underruns

     0 output errors, 0 collisions, 1 interface resets

     0 babbles, 0 late collision, 0 deferred

     0 lost carrier, 0 no carrier

     0 output buffer failures, 0 output buffers swapped out


Translating ""...domain server (dns provider1) (dns provider2)

% Unrecognized host or address, or protocol not running.

GUEST#ping w.x.y.z

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to w.x.y.z, timeout is 2 seconds:


Success rate is 0 percent (0/5)


John Blakley


Try changing your acl for nat to:

no access-list 100

access-list 100 permit ip any

And delete the ip route statement:

ip route FastEthernet0/1



HTH, John *** Please rate all useful posts ***

Your DHCP server is not serving a default gateway, so any traffic you send from a PC will not be able to get off the network. Also, for you to ping by name, make sure you use a valid DNS provider for the name server.

I would try pinging which is a known good internet DNS server. Kind of two birds with one stone, it's handy to ping to test and you can use it for DNS in a pinch. and are good to use also, they are google DNS servers.

Good luck!


Thanks its working!

Getting Started

Find answers to your questions by entering keywords or phrases in the Search bar above. New here? Use these resources to familiarize yourself with the community: