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Troubleshooting for PPPoE Connection Failure - Part 2 -

Here is "PPPoE Connection Failure - Part 2 -".Let me explain the specific examples I mentioned in Part 1.

3. Incorrect IP Address Configuration

For an incorrect IP address configuration, check whether the configuration is correct by referring to the documents for the ISP contract or the CCO documentation, but not the debug log.

PPPoE connection can be broadly categorized into two types depending on the IP address assignment method.One method is to automatically assign a dynamic IP address each time a connection is established, and the other method is to assign a static IP address in advance.

Please see the examples of connection configuration for each method on CCO.

Static IP assignment

Example configuration of PPPoE connection to a service provider that provides an IP address by LAN-type dispensing method

http://www.cisco.com/cisco/web/support/JP/102/1020/1020019_pppoe_lan.html

Automatic IP assignment

Example configuration of PPPoE connection to a service provider that provides an IP address by terminal-type dispensing method

http://www.cisco.com/cisco/web/support/JP/102/1020/1020018_pppoe_client.html

4. Debug Log for Incorrect Password Configuration

A debug log for incorrect password configuration is obtained.It may be difficult to notice if the debug log includes an incorrect password as well as other problems.

"Authentication failed" in the debug log indicates that the authentication has failed.After checking the ID / Password that you have configured, correct the incorrect configuration and confirm the operation.

A debug log for an incorrect password configuration

-----------------------------------------------------------------------------------

%LINK-3-UPDOWN: Interface Virtual-Access2, changed state to up

Vi2 PPP: Sending cstate UP notification

Vi2 PPP: Processing CstateUp message

PPP: Alloc Context [538C0B8]

ppp6 PPP: Phase is ESTABLISHING

Vi2 PPP: Using dialer call direction

Vi2 PPP: Treating connection as a callout

Vi2 PPP: Session handle[4F000006] Session id[6]

Vi2 LCP: Event[OPEN] State[Initial to Starting]

Vi2 PPP: No remote authentication for call-out

Vi2 LCP: O CONFREQ [Starting] id 1 len 14

Vi2 LCP:    MRU 1454 (0x010405AE)

Vi2 LCP:    MagicNumber 0x84212111 (0x050684212111)

Vi2 LCP: Event[UP] State[Starting to REQsent]

Vi2 LCP: I CONFREQ [REQsent] id 1 len 19

Vi2 LCP:    MRU 1454 (0x010405AE)

Vi2 LCP:    AuthProto CHAP (0x0305C22305)

Vi2 LCP:    MagicNumber 0x8420D234 (0x05068420D234)

Vi2 LCP: O CONFACK [REQsent] id 1 len 19

Vi2 LCP:    MRU 1454 (0x010405AE)

Vi2 LCP:    AuthProto CHAP (0x0305C22305)

Vi2 LCP:    MagicNumber 0x8420D234 (0x05068420D234)

Vi2 LCP: Event[Receive ConfReq+] State[REQsent to ACKsent]

Vi2 LCP: I CONFACK [ACKsent] id 1 len 14

Vi2 LCP:    MRU 1454 (0x010405AE)

Vi2 LCP:    MagicNumber 0x84212111 (0x050684212111)

Vi2 LCP: Event[Receive ConfAck] State[ACKsent to Open]

Vi2 PPP: Queue CHAP code[1] id[1]

Vi2 PPP: No authorization without authentication

Vi2 CHAP: Redirect packet to Vi2

Vi2 CHAP: I CHALLENGE id 1 len 31 from "PPPoE_Serv"

Vi2 PPP: Sent CHAP SENDAUTH Request

Vi2 LCP: State is Open

Vi2 PPP: Received SENDAUTH Response FAIL

Vi2 CHAP: Using hostname from interface CHAP

Vi2 CHAP: Using password from interface CHAP

Vi2 CHAP: O RESPONSE id 1 len 26 from "cisco"

Vi2 CHAP: I FAILURE id 1 len 25 msg is "Authentication failed"

Vi2 PPP DISC: We failed authentication

Vi2 LCP: I TERMREQ [Open] id 2 len 4

Vi2 LCP: O TERMACK [Open] id 2 len 4

Vi2 LCP: Event[Receive TermReq] State[Open to Stopping]

Vi2 PPP: Phase is TERMINATING

PPPoE 6: I PADT  R:aabb.cc00.d300 L:aabb.cc00.d400 Et0/0

PPPoE : Shutting down client session

[0]PPPoE 6: O PADT  R:aabb.cc00.d300 L:aabb.cc00.d400 Et0/0

%DIALER-6-UNBIND: Interface Vi2 unbound from profile Di1

Vi2 PPP: Block vaccess from being freed [0x10]

Vi2 LCP: Event[DOWN] State[Stopping to Starting]

Vi2 PPP: Unlocked by [0x10] Still Locked by [0x0]

Vi2 PPP: Free previously blocked vaccess

Vi2 PPP: Phase is DOWN

%LINK-3-UPDOWN: Interface Virtual-Access2, changed state to down

-----------------------------------------------------------------------------------

* "Authentication failed" is found after the negotiation of LCP is completed and the authentication is started with CHAP. After that, TERMREQ is received from the peer and TERMACK is returned, and then you can tell that the PPP session is terminated.

Original Document: https://supportforums.cisco.com/ja/document/92891
Author: Katsunori Ishizuka
Posted on February 23, 2012

Troubleshooting for PPPoE Connection Failure - Part 1 -
Troubleshooting for PPPoE Connection Failure - Part 3 -

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