Hello!
Roughly a year ago I bought a Cisco Series 1800 router and was able to configure it to serve as my home router. It was working perfectly for the 6-7 months without any issues. My ISP (Comcast) informed me that I needed to upgrade my modem to support the new DOCSIS 3.0 standard. I complied and swapped out my old Motorola Surfboard 5101U for a Arris Surfboard SB6141. Comcast then activated the new modem and I was able to connect to the internet by plugging in my laptop directly to the modem. However, when I plugged my Cisco router directly to the modem I was not able to gain external connectivity.
I checked the interface with the 'sh ip int brief' command and noticed that I no longer had an external IP address assigned to my WAN interface. I tried to clear the mac address thinking maybe the old Motorola MAC was still stuck but that did not resolve my issue. Also, I noticed that interface was stuck in a up/down so I am thinking there is a Layer-2 issue because I physically checked the cable and it works. I attempted to hardset the speed and duplex but this did not resolve the issue either. I also plugged in a dumb Linksys router directly to the modem and it can obtain an IP address and connect to the internet. However, I want my Cisco router to serve as my main GW.
Is there something that might have changed that I am not accounting for? Below I have provided my running-config and interface settings. I also provided a 'debug dhcp detail' output but its not extremely helpful.
Dogpound_c1800#show running-config
Dogpound_c1800#show running-config
Building configuration...
Current configuration : 2760 bytes
!
version 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
service password-encryption
!
hostname Dogpound_c1800
!
boot-start-marker
boot-end-marker
!
logging buffered 64000
enable secret 5 $1$LUXH$XE5Q99AQq1wB305gSXCSZ1
enable password 7 143A1319050A79282B3A231823010E185002594B487E551C0A16455A574543
!
no aaa new-model
!
!
!
!
!
!
ip cef
no ip dhcp use vrf connected
ip dhcp excluded-address 192.168.3.1
ip dhcp excluded-address 192.168.3.2
ip dhcp excluded-address 192.168.3.3
ip dhcp excluded-address 192.168.3.4
ip dhcp excluded-address 192.168.3.5
!
ip dhcp pool WIRELESS
import all
network 192.168.3.0 255.255.255.0
default-router 192.168.3.1
dns-server 8.8.8.8
!
!
ip ddns update method DynDNS
HTTP
add http://username:password@members.dyndns.org/nic/updatesystem=dyndns&hostname=<h>&myip=<a>
interval maximum 24 0 0 0
!
!
multilink bundle-name authenticated
!
!
username root password 7 123404051B055F07253934706A
archive
log config
hidekeys
!
!
ip ssh version 2
!
!
!
interface FastEthernet0
description COMCAST_WAN
ip ddns update hostname xxxxxxxx.xxxxxxx.org
ip ddns update DynDNS
ip address dhcp
ip nat outside
ip virtual-reassembly
duplex auto
speed auto
!
interface FastEthernet1
description INSIDE_INTERFACE
no ip address
duplex auto
speed auto
!
interface FastEthernet1.20
encapsulation dot1Q 20
ip address 192.168.2.1 255.255.255.0
!
interface FastEthernet1.30
description *WIRELESS_LAN*
encapsulation dot1Q 30
ip address 192.168.3.1 255.255.255.0
ip nat inside
ip virtual-reassembly
!
interface FastEthernet1.40
encapsulation dot1Q 40
ip address 192.168.4.1 255.255.255.0
!
interface FastEthernet1.50
description *MGMT*
encapsulation dot1Q 50
ip address 192.168.5.1 255.255.255.0
ip nat inside
ip virtual-reassembly
!
interface BRI0
no ip address
encapsulation hdlc
shutdown
isdn point-to-point-setup
!
interface FastEthernet2
shutdown
!
interface FastEthernet3
shutdown
!
interface FastEthernet4
shutdown
!
interface FastEthernet5
shutdown
!
interface FastEthernet6
shutdown
!
interface FastEthernet7
shutdown
!
interface FastEthernet8
shutdown
!
interface FastEthernet9
shutdown
!
interface Vlan1
no ip address
shutdown
!
ip route 0.0.0.0 0.0.0.0 73.251.210.1
!
!
ip http server
no ip http secure-server
ip nat inside source list 101 interface FastEthernet0 overload
!
access-list 101 permit ip 192.168.3.0 0.0.0.255 any
dialer-list 1 protocol ip permit
!
!
!
!
!
!
control-plane
!
banner login ^C
Unauthorized Access Prohibited!! Violators will be prosecuted!! ^C
!
line con 0
line aux 0
line vty 0 4
password 7 03295A190F01724F411B095D4E
login local
line vty 5 15
password 7 062B0E3345405A1A0A05025355
login local
!
!
webvpn cef
end
Dogpound_c1800#show ip int brief
Interface IP-Address OK? Method Status Protocol
FastEthernet0 unassigned YES NVRAM up down
FastEthernet1 unassigned YES NVRAM up up
FastEthernet1.20 192.168.2.1 YES NVRAM up up
FastEthernet1.30 192.168.3.1 YES NVRAM up up
FastEthernet1.40 192.168.4.1 YES NVRAM up up
FastEthernet1.50 192.168.5.1 YES NVRAM up up
BRI0 unassigned YES NVRAM administratively down down
BRI0:1 unassigned YES unset administratively down down
BRI0:2 unassigned YES unset administratively down down
FastEthernet2 unassigned YES unset administratively down down
FastEthernet3 unassigned YES unset administratively down down
FastEthernet4 unassigned YES unset administratively down down
FastEthernet5 unassigned YES unset administratively down down
FastEthernet6 unassigned YES unset administratively down down
FastEthernet7 unassigned YES unset administratively down down
FastEthernet8 unassigned YES unset administratively down down
FastEthernet9 unassigned YES unset administratively down down
Vlan1 unassigned YES NVRAM administratively down down
NVI0 unassigned NO unset up up
Dogpound_c1800#show run int fa0
Building configuration...
Current configuration : 212 bytes
!
interface FastEthernet0
description COMCAST_WAN
ip ddns update hostname dogpoundrouter.homedns.org
ip ddns update DynDNS
ip address dhcp
ip nat outside
ip virtual-reassembly
duplex auto
speed auto
end
Dogpound_c1800#show int fa0
FastEthernet0 is up, line protocol is down
Hardware is PQ3_TSEC, address is 0015.fa91.4d00 (bia 0015.fa91.4d00)
Description: COMCAST_WAN
Internet address will be negotiated using DHCP
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)
Auto-duplex, Auto Speed, 100BaseTX/FX
ARP type: ARPA, ARP Timeout 04:00:00
Last input never, output 00:00:00, output hang never
Last clearing of "show interface" counters never
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
0 packets input, 0 bytes
Received 0 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
188 packets output, 11280 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
Dogpound_c1800#show mac
Dogpound_c1800#show mac-address-table
Destination Address Address Type VLAN Destination Port
------------------- ------------ ---- --------------------
0015.fa91.4d00 Self 1 Vlan1
*Jul 3 16:53:45.575: %SYS-5-CONFIG_I: Configured from console by console
*Jul 3 16:54:00.719: DHCP: Waiting for 5 seconds on interface FastEthernet0 to come up
*Jul 3 16:54:05.719: DHCP: Waiting for 5 seconds on interface FastEthernet0 to come up
*Jul 3 16:54:10.719: DHCP: Waiting for 5 seconds on interface FastEthernet0 to come up
