Questions

Cisco 1721 ATT DSL Configuration HELP

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Cisco 1721 ATT DSL Configuration HELP

beast99
I am trying to learn Cisco so I bought a Cisco 1721 with a ADSL WIC and trying to configure to work with my ATT DSL Internet connection. All my interfaces shows UP, but I still cannot connect to the Internet. Can someone please help. Thank you in advance.

=====


Cisco_1721>
Cisco_1721>
Cisco_1721>
Cisco_1721>
Cisco_1721>en
Cisco_1721#sho run
Building configuration...

Current configuration : 1547 bytes
!
! No configuration change since last restart
!
version 12.3
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname Cisco_1721
!
boot-start-marker
boot-end-marker
!
logging buffered 4096 debugging
!
mmi polling-interval 60
no mmi auto-configure
no mmi pvc
mmi snmp-timeout 180
no aaa new-model
ip subnet-zero
!
!
ip dhcp excluded-address 192.168.1.1
!
ip dhcp pool HUYHO.NET
network 192.168.1.0 255.255.255.0
default-router 192.168.1.254
domain-name HUYHO.NET
dns-server 68.94.156.1 68.94.157.1
!
ip cef
!
!
bridge irb
!
!
interface ATM0
no ip address
no atm ilmi-keepalive
dsl operating-mode auto
bridge-group 1
pvc 0/35
encapsulation aal5snap
!
!
interface FastEthernet0
ip address 192.168.1.254 255.255.255.0
ip nat inside
speed auto
!
interface Serial0
no ip address
shutdown
no fair-queue
!
interface Dialer1
ip address negotiated
ip nat outside
encapsulation ppp
dialer pool 1
dialer-group 1
ppp authentication chap pap callin
ppp chap hostname xxxxxx
ppp chap password 0 xxxx
ppp pap sent-username xxxx password 0 xxxxx
ppp ipcp dns request accept
!
interface BVI1
mac-address 000d.ed1b.6478
ip address dhcp client-id FastEthernet0
ip nat outside
!
ip nat inside source list 1 interface Dialer1 overload
ip classless
ip route 0.0.0.0 0.0.0.0 Dialer1
no ip http server
!
!
access-list 1 permit 192.168.1.0 0.0.0.255
!
bridge 1 protocol ieee
bridge 1 route ip
!
line con 0
line aux 0
line vty 0 4
login
!
end

==============
Cisco_1721#sho ip int brief
Interface IP-Address OK? Method Status Prot
ocol
ATM0 unassigned YES NVRAM up up

BVI1 unassigned YES DHCP up up

Dialer1 unassigned YES NVRAM up up

FastEthernet0 192.168.1.254 YES NVRAM up up

Serial0 unassigned YES NVRAM administratively down dow

========

Thank You
Michael
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0 Votes
NetMan1958

Can you ping any websites ? Try pinging yahoo by the URL (www.yahoo.com) and by the IP Address (67.195.160.76) and post back with the results.

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0 Votes
beast99

Hello,
Thank you. I did try to ping both www.yahoo.com and 67.195.160.76 with NO success. When I try to ping www.yahoo.com, I get an error, unable to find host. When I try to ping the IP, I get an error Request TIme Out.

I have a crossover cable from the Cisco 1721 straight to the PC at this time.

Thank You
Michael

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0 Votes
beast99

One more thing. I got the ATT External DNS server (in my config above) just from doing a search in Yahoo. I did not call ATT to get this info. Not sure if this could be the problem?

Thank You
Michael

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0 Votes
NetMan1958

Take a look at this document and reconfigure your router in a similar way.
http://www.cisco.com/en/US/tech/tk175/tk15/technologies_configuration_example09186a008071a6c3.shtml
You shouldn't need bridging or the BVI interface. Also since your IOS version is 12.3 I don't think you will need the VPDN part of the configuration shown in the document. If you are not sure about the DNS server IPs, you can try using the OpenDNS servers (208.67.222.222
208.67.220.220) . If you still have problems, post back with the updated config.

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0 Votes
seanferd

See your old gateway or contact AT&T for the proper information - you may just have something wrong.

Maybe some Cisco hints here:
http://www.cisco.com/en/US/tech/tk175/tk15/technologies_q_and_a_item09186a0080093bff.shtml

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0 Votes
robo_dev

Sample ATT Cisco Config:

interface Dialer1
ip address negotiated
ip mtu 1492
ip nat outside
encapsulation ppp
ip tcp adjust-mss 1452
no ip mroute-cache
dialer pool 1
dialer-group 1
no cdp enable
ppp authentication pap callin
ppp pap sent-username [Enter username here without brackets] password [Enter password here without brackets]
ppp ipcp dns request
ppp ipcp address accept

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0 Votes
beast99

I did add in the DHCP accepted (please see below). I did verify my authentication with ATT as well and they are correct. They are also using CHAP. This maybe a dumb question since I am newbie with Cisco. Below under Interface Dialer1, I have (ppp pap sent-username xxxxx password 0 xxxxx) even though ATT is using CHAP, could this be a problem?

All my interfaces does still show all UP and I still not able to connect to the internet with my PC. Currently I am using a crossover cable to connect my PC directly to the Cisco 1721 router. Below is my complete config. Please help, thank you.

===
version 12.3
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname Cisco_1721
!
boot-start-marker
boot-end-marker
!
logging buffered 4096 debugging
!
mmi polling-interval 60
no mmi auto-configure
no mmi pvc
mmi snmp-timeout 180
no aaa new-model
ip subnet-zero
ip dhcp excluded-address 192.168.1.1
!
ip dhcp pool HUYHO.NET
network 192.168.1.0 255.255.255.0
default-router 192.168.1.254
domain-name HUYHO.NET
dns-server 68.94.156.1 68.94.157.1
!
ip cef
!
!
bridge irb
!
!
interface ATM0
no ip address
no atm ilmi-keepalive
dsl operating-mode auto
bridge-group 1
pvc 0/35
encapsulation aal5snap

interface FastEthernet0
ip address 192.168.1.254 255.255.255.0
ip nat inside
speed auto
!
interface Serial0
no ip address
shutdown
no fair-queue
!
interface Dialer1
ip address negotiated
ip nat outside
encapsulation ppp
dialer pool 1
dialer-group 1
ppp authentication chap callin
ppp chap hostname xxxxx
ppp chap password 0 xxxx
ppp pap sent-username xxxxx password 0 xxxxx
ppp ipcp dns request accept
ppp ipcp address accept

nterface BVI1
mac-address 000d.ed1b.6478
ip address dhcp client-id FastEthernet0
ip nat outside
!
ip nat inside source list 1 interface Dialer1 overload
ip classless
ip route 0.0.0.0 0.0.0.0 Dialer1
no ip http server
!
!
access-list 1 permit 192.168.1.0 0.0.0.255
!
bridge 1 protocol ieee
bridge 1 route ip
!
line con 0
line aux 0
line vty 0 4
login

==========

Cisco_1721#sho ip int breif
^
% Invalid input detected at '^' marker.

Cisco_1721#sho ip int brief
Interface IP-Address OK? Method Status Prot
ocol
ATM0 unassigned YES NVRAM up up

BVI1 unassigned YES DHCP up up

Dialer1 unassigned YES NVRAM up up

FastEthernet0 192.168.1.254 YES NVRAM up up

Serial0 unassigned YES NVRAM administratively down dow

==============

Thank You
Michael

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0 Votes
NetMan1958

You have interface ATM0 as a member of bridge-group 1. What is the purpose for that? Based on the output from your "sho ip int brief" you are not getting an IP Address from AT&T. Did you check out the article that I posted above:
http://www.cisco.com/en/US/tech/tk175/tk15/technologies_configuration_example09186a008071a6c3.shtml
?

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0 Votes
beast99

Hello,
When I had removed bridge-group 1 under my ATM0 Interface, the BVI1 interface keeps going down then up, down then up, down then up. It never stay UP. Below is my sho Int BVI1.

BVI1 is down, line protocol is down
Hardware is BVI, address is 000d.ed1b.6478 (bia 000d.ed1b.6478)
Internet address will be negotiated using DHCP
MTU 1500 bytes, BW 10000 Kbit, DLY 5000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
ARP type: ARPA, ARP Timeout 04:00:00
Last input never, output never, 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: 0/0 (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, 0 no buffer
Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
26 packets output, 16068 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 output buffer failures, 0 output buffers swapped out

Please help.

Thank You
Michael

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0 Votes
NetMan1958

Configure your interfaces as shown below:

interface FastEthernet0
ip address 192.168.1.254 255.255.255.0
ip tcp adjust-mss 1452
ip nat inside
speed auto
!
interface atm0
no shut
no ip address
bundle-enable
dsl operating-mode auto
!
interface atm0.1 point-to-point
no ip address
no ip directed-broadcast
no atm ilmi-keepalive
pvc 0/35
pppoe-client dial-pool-number 1
!
interface dialer1
ip address negotiated
mtu 1492
ip nat outside
encapsulation ppp
dialer pool 1
ppp authentication chap pap callin
ppp chap hostname <username>
ppp chap password <password>
ppp pap sent-username <username> password <password>
!
Then remove interface BVI1 and remove "bridge irb" and "bridge 1 protocol ieee" and "bridge 1 route ip". Then give it a go.

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0 Votes
beast99

Hello,
I did remove interface BVI1 and remove "bridge irb" and remove "bridge 1 protocol iee" and also remove "bridge 1 route. I also added ATM0.1 point-to-point but for some reason, I could not add pppoe-client dial-pool-number 1 under ATM0.1 point-to-point but was able to add pvc 0/35

All my interfaces shows up including ATM0 and ATM0.1 point-to-point, but for some reason ATM0 and ATM0.1 point-to-point is NOT pulling an IP address. I can ping the gateway fine and the PC that is connected directly to the router (with crossover cable) is getting an IP address (192.168.x.x)

Please advice. Thank you all for your help.

Thank You
Michael

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0 Votes
beast99

Hello,
I did remove interface BVI1 and remove "bridge irb" and remove "bridge 1 protocol iee" and also remove "bridge 1 route. I also added ATM0.1 point-to-point but for some reason, I could not add pppoe-client dial-pool-number 1 under ATM0.1 point-to-point but was able to add pvc 0/35

All my interfaces shows up including ATM0 and ATM0.1 point-to-point, but for some reason ATM0 and ATM0.1 point-to-point is NOT pulling an IP address. I can ping the gateway fine and the PC that is connected directly to the router (with crossover cable) is getting an IP address (192.168.x.x)

Please advice. Thank you all for your help.

Thank You
Michael .

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0 Votes
NetMan1958

If you go into interface config for ATM0.1 and type "ppoe?" and press ENTER , what is the output?