Troubleshooting guide

*Mar 1 04:04:58.722: Vi1 LCP: O CONFREQ [REQsent] id 5 Len 10
*Mar 1 04:04:58.722: Vi1 LCP: MagicNumber 0x317722F4 (0x0506317722F4)
*Mar 1 04:05:00.722: Vi1 LCP: TIMEout: State REQsent
*Mar 1 04:05:00.722: Vi1 LCP: O CONFREQ [REQsent] id 6 Len 10
*Mar 1 04:05:00.722: Vi1 LCP: MagicNumber 0x317722F4 (0x0506317722F4)
*Mar 1 04:05:02.722: Vi1 LCP: TIMEout: State REQsent
*Mar 1 04:05:02.722: Vi1 LCP: O CONFREQ [REQsent] id 7 Len 10
!−−− "O" specifies an outbound packet.
*Mar 1 04:05:02.722: Vi1 LCP: MagicNumber 0x317722F4 (0x0506317722F4)
Router#undebug all
In this output there are only O packets, which are outbound packets. To successfully negotiate PPP, there
should be an I inbound packet from your ISP for each O packet sent. If packets are incrementing inbound but
you don't see I packets, contact your ISP to verify the packets being sent to the Cisco DSL Router.
LCP Not Open
The LCP not being open is usually caused by a mismatch in PPP options. This mismatch occurs when the
Cisco DSL Router has a PPP parameter configured that your ISP does not support, or when your ISP has a
parameter configured that the Cisco DSL Router does not support. The following output shows an example of
a PPP option mismatch:
Router#debug ppp negotiation
*Mar 1 04:52:43.254: Vi1 PPP: Treating connection as a callout
*Mar 1 04:52:43.258: Vi1 PPP: Phase is ESTABLISHING, Active Open [0 sess, 1 load]
*Mar 1 04:52:43.258: Vi1 PPP: No remote authentication for call−out
*Mar 1 04:52:43.258: Vi1 LCP: O CONFREQ [Closed] id 3 len 10
*Mar 1 04:52:43.262: Vi1 LCP: MagicNumber 0x31A2F808 (0x050631A2F808)
*Mar 1 04:52:43.310: Vi1 LCP: I CONFREQ [REQsent] id 180 Len 14
*Mar 1 04:52:43.310: Vi1 LCP: AuthProto PAP (0x0304C023)
*Mar 1 04:52:43.310: Vi1 LCP: MagicNumber 0x39D50E9B (0x050639D50E9B)
*Mar 1 04:52:43.314: Vi1 LCP: O CONFNAK [REQsent] id 180 Len 9
!−−− PPP option reject.
*Mar 1 04:52:43.314: Vi1 LCP: AuthProto CHAP (0x0305C22305)
!−−− PPP option that is being rejected.
*Mar 1 04:52:43.314: Vi1 LCP: I CONFACK [REQsent] id 3 Len 10
*Mar 1 04:52:43.318: Vi1 LCP: MagicNumber 0x31A2F808 (0x050631A2F808)
*Mar 1 04:52:43.366: Vi1 LCP: I CONFREQ [ACKrcvd] id 181 Len 14
*Mar 1 04:52:43.366: Vi1 LCP: AuthProto PAP (0x0304C023)
*Mar 1 04:52:43.366: Vi1 LCP: MagicNumber 0x39D50E9B (0x050639D50E9B)
*Mar 1 04:52:43.370: Vi1 LCP: O CONFNAK [ACKrcvd] id 181 Len 9
!−−− PPP option reject.
*Mar 1 04:52:43.370: Vi1 LCP: AuthProto CHAP (0x0305C22305)
!−−− PPP option that is being rejected.
*Mar 1 04:52:43.418: Vi1 LCP: I CONFREQ [ACKrcvd] id 182 Len 14
*Mar 1 04:52:43.418: Vi1 LCP: AuthProto PAP (0x0304C023)
*Mar 1 04:52:43.418: Vi1 LCP: MagicNumber 0x39D50E9B (0x050639D50E9B)
Router#undebug all
Whether its an I or an O packet, a Configure−Negative−Acknowledge (CONFNAK) is indicative of a PPP
configuration mismatch. What this means is that one side of the PPP connection is asking for a PPP option
that the other side is unable or not configured to perform. If the Cisco DSL Router is sending the CONFNAK
(indicated by "O CONFNAK"), the Cisco DSL Router is not able to perform or not configured for the option
the ISP is sending. If the CONFNAK is being sent by your ISP (indicated by "I CONFNAK"), you have
configured an option on the Cisco DSL Router that your ISP is not willing to perform.
The line following the CONFNAK describes the option that is being rejected. In this example output, the
option is CHAP but it could be any option. The only place on the Cisco DSL Router where PPP options can
be configured is interface dialer 1. Issue the command show run interface dialer 1 to view your interface
Cisco DSL Router Configuration and Troubleshooting Guide