05-28-2008 01:41 PM - edited 03-03-2019 10:08 PM
Hi all.
I have a DSL bridge connected to the WAN port of a Cisco 831. For whatever reason, the 831 does not negotiate PPPoE. When I connect a simple Linksys router to the bridge, it works fine.
debug pppoe events on the 831 shows the following repeating loop:
Mar 31 : Sending PADI: Interface = Ethernet1
Mar 31 : padi timer expired
Mar 31 : Sending PADI: Interface = Ethernet1
Please check this out and let me know if I missed some configuration.
---------------------------------
!
version 12.4
no service pad
service timestamps debug datetime msec
service timestamps log datetime msec
service password-encryption
!
hostname Cisco831
!
boot-start-marker
boot-end-marker
!
logging buffered 51200 warnings
!
no aaa new-model
no ip dhcp use vrf connected
ip dhcp excluded-address 10.10.10.1
!
ip dhcp pool sdm-pool
import all
network 10.10.10.0 255.255.255.248
default-router 10.10.10.1
lease 0 2
!
!
ip cef
ip domain name yourdomain.com
vpdn enable
!
vpdn-group 1
request-dialin
protocol l2tp
domain global
!
!
username xxxxxxxx privilege 15 secret xxxxxxxx
!
!
!
!
bba-group pppoe global
virtual-template 1
!
!
interface Ethernet0
description $ETH-LAN$$ETH-SW-LAUNCH$$INTF-INFO-Ethernet 10/100$
ip address 10.10.10.1 255.255.255.248
ip nat inside
ip virtual-reassembly
ip tcp adjust-mss 1412
!
interface Ethernet1
description $ETH-WAN$
no ip address
ip mtu 1492
ip nat outside
ip virtual-reassembly
duplex auto
pppoe enable group global
pppoe-client dial-pool-number 1
!
interface Ethernet2
no ip address
shutdown
!
interface FastEthernet1
duplex auto
speed auto
!
interface FastEthernet2
duplex auto
speed auto
!
interface FastEthernet3
duplex auto
speed auto
!
interface FastEthernet4
duplex auto
speed auto
!
interface Dialer0
ip address negotiated
ip mtu 1452
ip nat outside
ip virtual-reassembly
encapsulation ppp
dialer pool 1
dialer-group 1
ppp authentication chap pap callin
ppp chap hostname xxxxxxxx
ppp chap password xxxxxxxx
ppp pap sent-username xxxxxxxx password xxxxxxxx
!
ip http server
ip http authentication local
ip http secure-server
ip http timeout-policy idle 60 life 86400 requests 10000
!
ip nat inside source list 1 interface Dialer0 overload
!
access-list 1 permit 10.10.10.0 0.0.0.7
dialer-list 1 protocol ip permit
!
line con 0
login local
no modem enable
line aux 0
line vty 0 4
privilege level 15
login local
transport input telnet ssh
!
scheduler max-task-time 5000
end
Solved! Go to Solution.
06-09-2008 07:43 PM
Hi,
Any luck determining the cause ? I have found in the past that after adding SSH access to a PPPoE config the unit fails to pass the PAP/CHAP authentication on the Dialer interface. I have yet to determine the breakdown
Regards,
Merlin
05-28-2008 01:43 PM
Question: Do I *have* to explicitly specify a MAC address on that interface?
The sh pppoe sessions is showing a MAC of all 0's.
06-10-2008 01:11 AM
If a PPPoE session has not been established, then the MAc address will show as all zeroes.
PPP negotiation only starts when there is a PPPoE session, so by the sounds of it the dialer won't have negotiated an IP address at this stage.
Are you still getting PADI timer expired debug messages? PADI is the first step of the discovery process -
1. PPPoE Active Discovery Initiation (PADI) packet
2. PPPoE Active Discovery Offer (PADO) packet
3. PPPoE Active Discovery Request (PADR) packet
4. PPPoE Active Discovery Session-confirmation (PADS) packet
5. PPPoE Active Discovery Terminate (PADT) packet
So if step one fails your PADI frames are not getting to the ISP or the ISP is not responding to this particular router.
Do you get anything helpful from any of the other PPPoE debugs?
#debug pppoe ?
data PPPoE data packets
elog PPPoE elogs
errors PPPoE protocol errors
events PPPoE protocol events
packets PPPoE control packets
There is a Cisco PPPoE troubleshooting page here:
http://www.cisco.com/en/US/tech/tk175/tk15/technologies_configuration_example09186a008071a7c2.shtml
However, after glancing at it, it seems to deal more with using an ATM interface as opposed to a fastethernet interface for the WAN connection.
05-28-2008 07:51 PM
Did the dialer get a IP address?
also you miss the default route
add
ip route 0.0.0.0 0.0.0.0 dialer0
06-09-2008 07:43 PM
Hi,
Any luck determining the cause ? I have found in the past that after adding SSH access to a PPPoE config the unit fails to pass the PAP/CHAP authentication on the Dialer interface. I have yet to determine the breakdown
Regards,
Merlin
06-12-2008 03:30 PM
Sorry for the delay in testing these suggestions. I've been fairly busy ;)
Anyways, I removed the SSH from the vty, just to eliminate that possible issue.
I also added ip route 0.0.0.0 0.0.0.0 dialer0.
The dialer0 interface never receives an IP address.
I've also turned on the debug for the dialer evens in addition to the pppoe events. This is the debug output that I'm getting now:
*Mar 31 01:33:23.271: PPPoE 6130: I PADT R:0090.1a40.c9b5 L:0016.c73e.352b Et1
*Mar 31 01:33:23.271: PPPoE : Shutting down client session
*Mar 31 01:33:23.271: [0]PPPoE 6130: O PADT R:0090.1a40.c9b5 L:0016.c73e.352b Et1
*Mar 31 01:33:23.271: %DIALER-6-UNBIND: Interface Vi2 unbound from profile Di0
*Mar 31 01:33:23.275: Vi2 DDR: disconnecting call
*Mar 31 01:33:23.275: %LINK-3-UPDOWN: Interface Virtual-Access2, changed state to down
*Mar 31 01:33:24.255: %LINEPROTO-5-UPDOWN: Line protocol on Interface Virtual-Access2, changed state to down
*Mar 31 01:33:31.507: Di0 DDR: Cannot place call, no dialer string set
*Mar 31 01:33:34.991: Di0 DDR: Cannot place call, no dialer string set
*Mar 31 01:33:38.991: Di0 DDR: Cannot place call, no dialer string set
*Mar 31 01:33:43.395: Sending PADI: Interface = Ethernet1
*Mar 31 01:33:43.411: PPPoE 0: I PADO R:0090.1a40.c9b5 L:0016.c73e.352b Et1
*Mar 31 01:33:45.475: PPPOE: we've got our pado and the pado timer went off
*Mar 31 01:33:45.475: OUT PADR from PPPoE Session
*Mar 31 01:33:45.487: PPPoE 6152: I PADS R:0090.1a40.c9b5 L:0016.c73e.352b Et1
*Mar 31 01:33:45.491: IN PADS from PPPoE Session
*Mar 31 01:33:45.495: %DIALER-6-BIND: Interface Vi2 bound to profile Di0
*Mar 31 01:33:45.495: PPPoE: Virtual Access interface obtained.
*Mar 31 01:33:45.495: PPPoE : encap string prepared
*Mar 31 01:33:45.495: [0]PPPoE 6152: data path set to Virtual Acess
*Mar 31 01:33:45.499: %LINK-3-UPDOWN: Interface Virtual-Access2, changed state to up
*Mar 31 01:33:45.499: Vi2 DDR: Dialer statechange to up
*Mar 31 01:33:49.015: Vi2 DDR: dialer protocol up
*Mar 31 01:33:49.971: %LINEPROTO-5-UPDOWN: Line protocol on Interface Virtual-Access2, changed state to up
To my unexperienced eye, it looks like I'm getting PADI and PADO functioning. I'm not sure where the Vi2 interface comes into the picture, I never configured it... Anybody got a suggestion?
06-12-2008 03:46 PM
PPPoE is OK. Now undeb that and take debug ppp auth, debug ppp neg.
06-12-2008 06:35 PM
Thanks for all the help everyone.
After viewing the ppp auth debug I realized that my IP address is not assigned via DHCP but rather it should have been set to ppp negotiated.
Problem solved! Thanks again.
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