LCP problem. - PPP

This is a discussion on LCP problem. - PPP ; Hi, I'm experiencing a strange problem. In my setup the PPP link is running over PPPoE, and I use windows XP+ RASPPPOE to simulate access concentrator and my machine (PPC based, embedded machine) as the client. During the LCP I ...

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Thread: LCP problem.

  1. LCP problem.

    Hi,
    I'm experiencing a strange problem.
    In my setup the PPP link is running over PPPoE, and I use windows XP+
    RASPPPOE to simulate access concentrator and my machine (PPC based,
    embedded machine) as the client.

    During the LCP I negotiate for PAP, MRU & magic number. Now strangely,
    after the server had negotiated successfully and received
    configure-ack and the auth process acked by the server as well, it
    sends conf-request again (immediately! no timeout...)

    Here is a capture. As you can see in packet 8 the server received
    conf-ack (the capture was taken on the server machine), packets 9 & 10
    are the PAP and though there is an authenticate-ack, it sends again
    conf request in packet 11...

    Can someone shade some light on this behavior?

    10x in advance.
    wd.

    No. Time Source Destination
    Protocol Info
    1 72.360670 10.31.174.26 10.31.2.14 PPP LCP
    Configuration Request

    Frame 362 (60 bytes on wire, 60 bytes captured)
    Arrival Time: May 25, 2004 17:56:52.588018000
    Time delta from previous packet: 1.058451000 seconds
    Time since reference or first frame: 72.360670000 seconds
    Frame Number: 362
    Packet Length: 60 bytes
    Capture Length: 60 bytes
    Ethernet II, Src: 00:90:8f:03:b5:32, Dst: 00:02:b3:04:e7:76
    Destination: 00:02:b3:04:e7:76 (10.31.2.14)
    Source: 00:90:8f:03:b5:32 (10.31.174.26)
    Type: PPPoE Session (0x8864)
    PPP-over-Ethernet Session
    Version: 1
    Type: 1
    Code: Session Data
    Session ID: 00b2
    Payload Length: 20
    Point-to-Point Protocol
    Protocol: Link Control Protocol (0xc021)
    PPP Link Control Protocol
    Code: Configuration Request (0x01)
    Identifier: 0x00
    Length: 18
    Options: (14 bytes)
    Maximum Receive Unit: 1492
    Authentication protocol: 4 bytes
    Authentication protocol: Password Authentication Protocol
    (0xc023)
    Magic number: 0x12348765

    0000 00 02 b3 04 e7 76 00 90 8f 03 b5 32 88 64 11 00
    ......v.....2.d..
    0010 00 b2 00 14 c0 21 01 00 00 12 01 04 05 d4 03 04
    ......!..........
    0020 c0 23 05 06 12 34 87 65 c0 23 05 06 12 34 87 65
    ..#...4.e.#...4.e
    0030 c4 01 01 01 00 00 00 00 00 00 00 00 ............

    No. Time Source Destination
    Protocol Info
    2 72.363365 10.31.2.14 10.31.174.26 PPP LCP
    Configuration Request

    Frame 363 (75 bytes on wire, 75 bytes captured)
    Arrival Time: May 25, 2004 17:56:52.590713000
    Time delta from previous packet: 0.002695000 seconds
    Time since reference or first frame: 72.363365000 seconds
    Frame Number: 363
    Packet Length: 75 bytes
    Capture Length: 75 bytes
    Ethernet II, Src: 00:02:b3:04:e7:76, Dst: 00:90:8f:03:b5:32
    Destination: 00:90:8f:03:b5:32 (10.31.174.26)
    Source: 00:02:b3:04:e7:76 (10.31.2.14)
    Type: PPPoE Session (0x8864)
    PPP-over-Ethernet Session
    Version: 1
    Type: 1
    Code: Session Data
    Session ID: 00b2
    Payload Length: 55
    Point-to-Point Protocol
    Protocol: Link Control Protocol (0xc021)
    PPP Link Control Protocol
    Code: Configuration Request (0x01)
    Identifier: 0x00
    Length: 53
    Options: (49 bytes)
    Maximum Receive Unit: 1492
    Authentication protocol: 5 bytes
    Authentication protocol: Challenge Handshake
    Authentication Protocol (0xc223)
    Algorithm: MS-CHAP-2 (0x81)
    Magic number: 0x278d5720
    Callback: 3 bytes
    Operation: Location is determined during CBCP negotiation
    (0x06)
    Multilink MRRU: 1614
    Multilink endpoint discriminator: 23 bytes
    Class: Locally assigned address (1)
    Address (20 bytes)
    Link discriminator for BAP: 0x002d

    0000 00 90 8f 03 b5 32 00 02 b3 04 e7 76 88 64 11 00
    ......2.....v.d..
    0010 00 b2 00 37 c0 21 01 00 00 35 01 04 05 d4 03 05
    ....7.!...5......
    0020 c2 23 81 05 06 27 8d 57 20 0d 03 06 11 04 06 4e .#...'.W
    .......N
    0030 13 17 01 07 c1 c6 a4 d9 cb 41 a4 9f d5 3d 6d 43
    ..........A...=mC
    0040 46 7f b4 00 00 00 00 17 04 00 2d F.........-

    No. Time Source Destination
    Protocol Info
    3 72.363743 10.31.2.14 10.31.174.26 PPP LCP
    Configuration Ack

    Frame 364 (40 bytes on wire, 40 bytes captured)
    Arrival Time: May 25, 2004 17:56:52.591091000
    Time delta from previous packet: 0.000378000 seconds
    Time since reference or first frame: 72.363743000 seconds
    Frame Number: 364
    Packet Length: 40 bytes
    Capture Length: 40 bytes
    Ethernet II, Src: 00:02:b3:04:e7:76, Dst: 00:90:8f:03:b5:32
    Destination: 00:90:8f:03:b5:32 (10.31.174.26)
    Source: 00:02:b3:04:e7:76 (10.31.2.14)
    Type: PPPoE Session (0x8864)
    PPP-over-Ethernet Session
    Version: 1
    Type: 1
    Code: Session Data
    Session ID: 00b2
    Payload Length: 20
    Point-to-Point Protocol
    Protocol: Link Control Protocol (0xc021)
    PPP Link Control Protocol
    Code: Configuration Ack (0x02)
    Identifier: 0x00
    Length: 18
    Options: (14 bytes)
    Maximum Receive Unit: 1492
    Authentication protocol: 4 bytes
    Authentication protocol: Password Authentication Protocol
    (0xc023)
    Magic number: 0x12348765

    0000 00 90 8f 03 b5 32 00 02 b3 04 e7 76 88 64 11 00
    ......2.....v.d..
    0010 00 b2 00 14 c0 21 02 00 00 12 01 04 05 d4 03 04
    ......!..........
    0020 c0 23 05 06 12 34 87 65 .#...4.e

    No. Time Source Destination
    Protocol Info
    4 72.477406 10.31.174.26 10.31.2.14 PPP LCP
    Configuration Reject

    Frame 365 (60 bytes on wire, 60 bytes captured)
    Arrival Time: May 25, 2004 17:56:52.704754000
    Time delta from previous packet: 0.113663000 seconds
    Time since reference or first frame: 72.477406000 seconds
    Frame Number: 365
    Packet Length: 60 bytes
    Capture Length: 60 bytes
    Ethernet II, Src: 00:90:8f:03:b5:32, Dst: 00:02:b3:04:e7:76
    Destination: 00:02:b3:04:e7:76 (10.31.2.14)
    Source: 00:90:8f:03:b5:32 (10.31.174.26)
    Type: PPPoE Session (0x8864)
    PPP-over-Ethernet Session
    Version: 1
    Type: 1
    Code: Session Data
    Session ID: 00b2
    Payload Length: 36
    Point-to-Point Protocol
    Protocol: Link Control Protocol (0xc021)
    PPP Link Control Protocol
    Code: Configuration Reject (0x04)
    Identifier: 0x00
    Length: 34
    Options: (30 bytes)
    Callback: 3 bytes
    Operation: Location is determined during CBCP negotiation
    (0x06)
    Multilink MRRU: 1614
    Multilink endpoint discriminator: 23 bytes
    Class: Locally assigned address (1)
    Address (20 bytes)

    0000 00 02 b3 04 e7 76 00 90 8f 03 b5 32 88 64 11 00
    ......v.....2.d..
    0010 00 b2 00 24 c0 21 04 00 00 22 0d 03 06 11 04 06
    ....$.!..."......
    0020 4e 13 17 01 07 c1 c6 a4 d9 cb 41 a4 9f d5 3d 6d
    N.........A...=m
    0030 43 46 7f b4 00 00 00 00 4e 13 17 01 CF......N...

    No. Time Source Destination
    Protocol Info
    5 72.477924 10.31.2.14 10.31.174.26 PPP LCP
    Configuration Request

    Frame 366 (45 bytes on wire, 45 bytes captured)
    Arrival Time: May 25, 2004 17:56:52.705272000
    Time delta from previous packet: 0.000518000 seconds
    Time since reference or first frame: 72.477924000 seconds
    Frame Number: 366
    Packet Length: 45 bytes
    Capture Length: 45 bytes
    Ethernet II, Src: 00:02:b3:04:e7:76, Dst: 00:90:8f:03:b5:32
    Destination: 00:90:8f:03:b5:32 (10.31.174.26)
    Source: 00:02:b3:04:e7:76 (10.31.2.14)
    Type: PPPoE Session (0x8864)
    PPP-over-Ethernet Session
    Version: 1
    Type: 1
    Code: Session Data
    Session ID: 00b2
    Payload Length: 25
    Point-to-Point Protocol
    Protocol: Link Control Protocol (0xc021)
    PPP Link Control Protocol
    Code: Configuration Request (0x01)
    Identifier: 0x01
    Length: 23
    Options: (19 bytes)
    Maximum Receive Unit: 1492
    Authentication protocol: 5 bytes
    Authentication protocol: Challenge Handshake
    Authentication Protocol (0xc223)
    Algorithm: MS-CHAP-2 (0x81)
    Magic number: 0x278d5720
    Link discriminator for BAP: 0x002d

    0000 00 90 8f 03 b5 32 00 02 b3 04 e7 76 88 64 11 00
    ......2.....v.d..
    0010 00 b2 00 19 c0 21 01 01 00 17 01 04 05 d4 03 05
    ......!..........
    0020 c2 23 81 05 06 27 8d 57 20 17 04 00 2d .#...'.W ...-

    No. Time Source Destination
    Protocol Info
    6 72.499547 10.31.174.26 10.31.2.14 PPP LCP
    Configuration Nak

    Frame 367 (60 bytes on wire, 60 bytes captured)
    Arrival Time: May 25, 2004 17:56:52.726895000
    Time delta from previous packet: 0.021623000 seconds
    Time since reference or first frame: 72.499547000 seconds
    Frame Number: 367
    Packet Length: 60 bytes
    Capture Length: 60 bytes
    Ethernet II, Src: 00:90:8f:03:b5:32, Dst: 00:02:b3:04:e7:76
    Destination: 00:02:b3:04:e7:76 (10.31.2.14)
    Source: 00:90:8f:03:b5:32 (10.31.174.26)
    Type: PPPoE Session (0x8864)
    PPP-over-Ethernet Session
    Version: 1
    Type: 1
    Code: Session Data
    Session ID: 00b2
    Payload Length: 10
    Point-to-Point Protocol
    Protocol: Link Control Protocol (0xc021)
    PPP Link Control Protocol
    Code: Configuration Nak (0x03)
    Identifier: 0x01
    Length: 8
    Options: (4 bytes)
    Authentication protocol: 4 bytes
    Authentication protocol: Password Authentication Protocol
    (0xc023)

    0000 00 02 b3 04 e7 76 00 90 8f 03 b5 32 88 64 11 00
    ......v.....2.d..
    0010 00 b2 00 0a c0 21 03 01 00 08 03 04 c0 23 00 02
    ......!.......#..
    0020 b3 04 e7 76 00 90 8f 03 b5 32 88 64 11 00 00 b2
    ....v.....2.d....
    0030 00 0a c0 21 03 01 00 08 03 04 c0 23 ...!.......#

    No. Time Source Destination
    Protocol Info
    7 72.499892 10.31.2.14 10.31.174.26 PPP LCP
    Configuration Request

    Frame 368 (44 bytes on wire, 44 bytes captured)
    Arrival Time: May 25, 2004 17:56:52.727240000
    Time delta from previous packet: 0.000345000 seconds
    Time since reference or first frame: 72.499892000 seconds
    Frame Number: 368
    Packet Length: 44 bytes
    Capture Length: 44 bytes
    Ethernet II, Src: 00:02:b3:04:e7:76, Dst: 00:90:8f:03:b5:32
    Destination: 00:90:8f:03:b5:32 (10.31.174.26)
    Source: 00:02:b3:04:e7:76 (10.31.2.14)
    Type: PPPoE Session (0x8864)
    PPP-over-Ethernet Session
    Version: 1
    Type: 1
    Code: Session Data
    Session ID: 00b2
    Payload Length: 24
    Point-to-Point Protocol
    Protocol: Link Control Protocol (0xc021)
    PPP Link Control Protocol
    Code: Configuration Request (0x01)
    Identifier: 0x02
    Length: 22
    Options: (18 bytes)
    Maximum Receive Unit: 1492
    Authentication protocol: 4 bytes
    Authentication protocol: Password Authentication Protocol
    (0xc023)
    Magic number: 0x278d5720
    Link discriminator for BAP: 0x002d

    0000 00 90 8f 03 b5 32 00 02 b3 04 e7 76 88 64 11 00
    ......2.....v.d..
    0010 00 b2 00 18 c0 21 01 02 00 16 01 04 05 d4 03 04
    ......!..........
    0020 c0 23 05 06 27 8d 57 20 17 04 00 2d .#..'.W ...-

    No. Time Source Destination
    Protocol Info
    8 72.512439 10.31.174.26 10.31.2.14 PPP LCP
    Configuration Ack

    Frame 369 (60 bytes on wire, 60 bytes captured)
    Arrival Time: May 25, 2004 17:56:52.739787000
    Time delta from previous packet: 0.012547000 seconds
    Time since reference or first frame: 72.512439000 seconds
    Frame Number: 369
    Packet Length: 60 bytes
    Capture Length: 60 bytes
    Ethernet II, Src: 00:90:8f:03:b5:32, Dst: 00:02:b3:04:e7:76
    Destination: 00:02:b3:04:e7:76 (10.31.2.14)
    Source: 00:90:8f:03:b5:32 (10.31.174.26)
    Type: PPPoE Session (0x8864)
    PPP-over-Ethernet Session
    Version: 1
    Type: 1
    Code: Session Data
    Session ID: 00b2
    Payload Length: 24
    Point-to-Point Protocol
    Protocol: Link Control Protocol (0xc021)
    PPP Link Control Protocol
    Code: Configuration Ack (0x02)
    Identifier: 0x02
    Length: 22
    Options: (18 bytes)
    Maximum Receive Unit: 1492
    Authentication protocol: 4 bytes
    Authentication protocol: Password Authentication Protocol
    (0xc023)
    Magic number: 0x278d5720
    Link discriminator for BAP: 0x002d

    0000 00 02 b3 04 e7 76 00 90 8f 03 b5 32 88 64 11 00
    ......v.....2.d..
    0010 00 b2 00 18 c0 21 02 02 00 16 01 04 05 d4 03 04
    ......!..........
    0020 c0 23 05 06 27 8d 57 20 17 04 00 2d c0 23 05 06 .#..'.W
    ....-.#..
    0030 27 8d 57 20 17 04 00 2d 9f d5 3d 6d '.W ...-..=m

    No. Time Source Destination
    Protocol Info
    9 72.512535 10.31.174.26 10.31.2.14 PPP PAP
    Authenticate-Request

    Frame 370 (60 bytes on wire, 60 bytes captured)
    Arrival Time: May 25, 2004 17:56:52.739883000
    Time delta from previous packet: 0.000096000 seconds
    Time since reference or first frame: 72.512535000 seconds
    Frame Number: 370
    Packet Length: 60 bytes
    Capture Length: 60 bytes
    Ethernet II, Src: 00:90:8f:03:b5:32, Dst: 00:02:b3:04:e7:76
    Destination: 00:02:b3:04:e7:76 (10.31.2.14)
    Source: 00:90:8f:03:b5:32 (10.31.174.26)
    Type: PPPoE Session (0x8864)
    PPP-over-Ethernet Session
    Version: 1
    Type: 1
    Code: Session Data
    Session ID: 00b2
    Payload Length: 17
    Point-to-Point Protocol
    Protocol: Password Authentication Protocol (0xc023)
    PPP Password Authentication Protocol
    Code: Authenticate-Request (0x01)
    Identifier: 0x01
    Length: 15
    Data (11 bytes)
    Peer ID length: 4 bytes
    Peer-ID (4 bytes)
    Password length: 5 bytes
    Password (5 bytes)

    0000 00 02 b3 04 e7 76 00 90 8f 03 b5 32 88 64 11 00
    ......v.....2.d..
    0010 00 b2 00 11 c0 23 01 01 00 0f 04 75 73 65 72 05
    ......#.....user.
    0020 31 32 33 34 35 31 32 33 34 35 00 00 00 00 00 00
    1234512345......
    0030 00 00 00 00 00 00 00 00 00 00 00 00 ............

    No. Time Source Destination
    Protocol Info
    10 72.519921 10.31.2.14 10.31.174.26 PPP PAP
    Authenticate-Ack

    Frame 371 (27 bytes on wire, 27 bytes captured)
    Arrival Time: May 25, 2004 17:56:52.747269000
    Time delta from previous packet: 0.007386000 seconds
    Time since reference or first frame: 72.519921000 seconds
    Frame Number: 371
    Packet Length: 27 bytes
    Capture Length: 27 bytes
    Ethernet II, Src: 00:02:b3:04:e7:76, Dst: 00:90:8f:03:b5:32
    Destination: 00:90:8f:03:b5:32 (10.31.174.26)
    Source: 00:02:b3:04:e7:76 (10.31.2.14)
    Type: PPPoE Session (0x8864)
    PPP-over-Ethernet Session
    Version: 1
    Type: 1
    Code: Session Data
    Session ID: 00b2
    Payload Length: 7
    Point-to-Point Protocol
    Protocol: Password Authentication Protocol (0xc023)
    PPP Password Authentication Protocol
    Code: Authenticate-Ack (0x02)
    Identifier: 0x01
    Length: 5
    Data (1 byte)
    Message length: 0 bytes

    0000 00 90 8f 03 b5 32 00 02 b3 04 e7 76 88 64 11 00
    ......2.....v.d..
    0010 00 b2 00 07 c0 23 02 01 00 05 00 .....#.....

    No. Time Source Destination
    Protocol Info
    11 72.522775 10.31.2.14 10.31.174.26 PPP LCP
    Configuration Request

    Frame 372 (75 bytes on wire, 75 bytes captured)
    Arrival Time: May 25, 2004 17:56:52.750123000
    Time delta from previous packet: 0.002854000 seconds
    Time since reference or first frame: 72.522775000 seconds
    Frame Number: 372
    Packet Length: 75 bytes
    Capture Length: 75 bytes
    Ethernet II, Src: 00:02:b3:04:e7:76, Dst: 00:90:8f:03:b5:32
    Destination: 00:90:8f:03:b5:32 (10.31.174.26)
    Source: 00:02:b3:04:e7:76 (10.31.2.14)
    Type: PPPoE Session (0x8864)
    PPP-over-Ethernet Session
    Version: 1
    Type: 1
    Code: Session Data
    Session ID: 00b2
    Payload Length: 55
    Point-to-Point Protocol
    Protocol: Link Control Protocol (0xc021)
    PPP Link Control Protocol
    Code: Configuration Request (0x01)
    Identifier: 0x04
    Length: 53
    Options: (49 bytes)
    Maximum Receive Unit: 1492
    Authentication protocol: 5 bytes
    Authentication protocol: Challenge Handshake
    Authentication Protocol (0xc223)
    Algorithm: MS-CHAP-2 (0x81)
    Magic number: 0x299714e1
    Callback: 3 bytes
    Operation: Location is determined during CBCP negotiation
    (0x06)
    Multilink MRRU: 1614
    Multilink endpoint discriminator: 23 bytes
    Class: Locally assigned address (1)
    Address (20 bytes)
    Link discriminator for BAP: 0x002d

    0000 00 90 8f 03 b5 32 00 02 b3 04 e7 76 88 64 11 00
    ......2.....v.d..
    0010 00 b2 00 37 c0 21 01 04 00 35 01 04 05 d4 03 05
    ....7.!...5......
    0020 c2 23 81 05 06 29 97 14 e1 0d 03 06 11 04 06 4e
    ..#...).........N
    0030 13 17 01 07 c1 c6 a4 d9 cb 41 a4 9f d5 3d 6d 43
    ..........A...=mC
    0040 46 7f b4 00 00 00 00 17 04 00 2d F.........-

    No. Time Source Destination
    Protocol Info
    12 72.523479 10.31.174.26 10.31.2.14 PPP LCP
    Configuration Request

    Frame 373 (60 bytes on wire, 60 bytes captured)
    Arrival Time: May 25, 2004 17:56:52.750827000
    Time delta from previous packet: 0.000704000 seconds
    Time since reference or first frame: 72.523479000 seconds
    Frame Number: 373
    Packet Length: 60 bytes
    Capture Length: 60 bytes
    Ethernet II, Src: 00:90:8f:03:b5:32, Dst: 00:02:b3:04:e7:76
    Destination: 00:02:b3:04:e7:76 (10.31.2.14)
    Source: 00:90:8f:03:b5:32 (10.31.174.26)
    Type: PPPoE Session (0x8864)
    PPP-over-Ethernet Session
    Version: 1
    Type: 1
    Code: Session Data
    Session ID: 00b2
    Payload Length: 20
    Point-to-Point Protocol
    Protocol: Link Control Protocol (0xc021)
    PPP Link Control Protocol
    Code: Configuration Request (0x01)
    Identifier: 0x01
    Length: 18
    Options: (14 bytes)
    Maximum Receive Unit: 1492
    Authentication protocol: 4 bytes
    Authentication protocol: Password Authentication Protocol
    (0xc023)
    Magic number: 0x12348765

    0000 00 02 b3 04 e7 76 00 90 8f 03 b5 32 88 64 11 00
    ......v.....2.d..
    0010 00 b2 00 14 c0 21 01 01 00 12 01 04 05 d4 03 04
    ......!..........
    0020 c0 23 05 06 12 34 87 65 c0 23 05 06 12 34 87 65
    ..#...4.e.#...4.e
    0030 00 00 00 00 00 00 00 00 00 00 00 00 ............

    No. Time Source Destination
    Protocol Info
    13 72.523523 10.31.174.26 10.31.2.14 PPP LCP
    Configuration Reject

    Frame 374 (60 bytes on wire, 60 bytes captured)
    Arrival Time: May 25, 2004 17:56:52.750871000
    Time delta from previous packet: 0.000044000 seconds
    Time since reference or first frame: 72.523523000 seconds
    Frame Number: 374
    Packet Length: 60 bytes
    Capture Length: 60 bytes
    Ethernet II, Src: 00:90:8f:03:b5:32, Dst: 00:02:b3:04:e7:76
    Destination: 00:02:b3:04:e7:76 (10.31.2.14)
    Source: 00:90:8f:03:b5:32 (10.31.174.26)
    Type: PPPoE Session (0x8864)
    PPP-over-Ethernet Session
    Version: 1
    Type: 1
    Code: Session Data
    Session ID: 00b2
    Payload Length: 36
    Point-to-Point Protocol
    Protocol: Link Control Protocol (0xc021)
    PPP Link Control Protocol
    Code: Configuration Reject (0x04)
    Identifier: 0x04
    Length: 34
    Options: (30 bytes)
    Callback: 3 bytes
    Operation: Location is determined during CBCP negotiation
    (0x06)
    Multilink MRRU: 1614
    Multilink endpoint discriminator: 23 bytes
    Class: Locally assigned address (1)
    Address (20 bytes)

    0000 00 02 b3 04 e7 76 00 90 8f 03 b5 32 88 64 11 00
    ......v.....2.d..
    0010 00 b2 00 24 c0 21 04 04 00 22 0d 03 06 11 04 06
    ....$.!..."......
    0020 4e 13 17 01 07 c1 c6 a4 d9 cb 41 a4 9f d5 3d 6d
    N.........A...=m
    0030 43 46 7f b4 00 00 00 00 4e 13 17 01 CF......N...

    No. Time Source Destination
    Protocol Info
    15 72.523899 10.31.2.14 10.31.174.26 PPP LCP
    Configuration Reject

    Frame 375 (30 bytes on wire, 30 bytes captured)
    Arrival Time: May 25, 2004 17:56:52.751247000
    Time delta from previous packet: 0.000376000 seconds
    Time since reference or first frame: 72.523899000 seconds
    Frame Number: 375
    Packet Length: 30 bytes
    Capture Length: 30 bytes
    Ethernet II, Src: 00:02:b3:04:e7:76, Dst: 00:90:8f:03:b5:32
    Destination: 00:90:8f:03:b5:32 (10.31.174.26)
    Source: 00:02:b3:04:e7:76 (10.31.2.14)
    Type: PPPoE Session (0x8864)
    PPP-over-Ethernet Session
    Version: 1
    Type: 1
    Code: Session Data
    Session ID: 00b2
    Payload Length: 10
    Point-to-Point Protocol
    Protocol: Link Control Protocol (0xc021)
    PPP Link Control Protocol
    Code: Configuration Reject (0x04)
    Identifier: 0x01
    Length: 8
    Options: (4 bytes)
    Authentication protocol: 4 bytes
    Authentication protocol: Password Authentication Protocol
    (0xc023)

    0000 00 90 8f 03 b5 32 00 02 b3 04 e7 76 88 64 11 00
    ......2.....v.d..
    0010 00 b2 00 0a c0 21 04 01 00 08 03 04 c0 23 .....!.......#

    No. Time Source Destination
    Protocol Info
    16 72.524240 10.31.2.14 10.31.174.26 PPP LCP
    Configuration Request

    Frame 376 (45 bytes on wire, 45 bytes captured)
    Arrival Time: May 25, 2004 17:56:52.751588000
    Time delta from previous packet: 0.000341000 seconds
    Time since reference or first frame: 72.524240000 seconds
    Frame Number: 376
    Packet Length: 45 bytes
    Capture Length: 45 bytes
    Ethernet II, Src: 00:02:b3:04:e7:76, Dst: 00:90:8f:03:b5:32
    Destination: 00:90:8f:03:b5:32 (10.31.174.26)
    Source: 00:02:b3:04:e7:76 (10.31.2.14)
    Type: PPPoE Session (0x8864)
    PPP-over-Ethernet Session
    Version: 1
    Type: 1
    Code: Session Data
    Session ID: 00b2
    Payload Length: 25
    Point-to-Point Protocol
    Protocol: Link Control Protocol (0xc021)
    PPP Link Control Protocol
    Code: Configuration Request (0x01)
    Identifier: 0x05
    Length: 23
    Options: (19 bytes)
    Maximum Receive Unit: 1492
    Authentication protocol: 5 bytes
    Authentication protocol: Challenge Handshake
    Authentication Protocol (0xc223)
    Algorithm: MS-CHAP-2 (0x81)
    Magic number: 0x299714e1
    Link discriminator for BAP: 0x002d

    0000 00 90 8f 03 b5 32 00 02 b3 04 e7 76 88 64 11 00
    ......2.....v.d..
    0010 00 b2 00 19 c0 21 01 05 00 17 01 04 05 d4 03 05
    ......!..........
    0020 c2 23 81 05 06 29 97 14 e1 17 04 00 2d .#...)......-

    No. Time Source Destination
    Protocol Info
    17 72.524344 10.31.174.26 10.31.2.14 PPP LCP
    Termination Request

    Frame 377 (60 bytes on wire, 60 bytes captured)
    Arrival Time: May 25, 2004 17:56:52.751692000
    Time delta from previous packet: 0.000104000 seconds
    Time since reference or first frame: 72.524344000 seconds
    Frame Number: 377
    Packet Length: 60 bytes
    Capture Length: 60 bytes
    Ethernet II, Src: 00:90:8f:03:b5:32, Dst: 00:02:b3:04:e7:76
    Destination: 00:02:b3:04:e7:76 (10.31.2.14)
    Source: 00:90:8f:03:b5:32 (10.31.174.26)
    Type: PPPoE Session (0x8864)
    PPP-over-Ethernet Session
    Version: 1
    Type: 1
    Code: Session Data
    Session ID: 00b2
    Payload Length: 6
    Point-to-Point Protocol
    Protocol: Link Control Protocol (0xc021)
    PPP Link Control Protocol
    Code: Termination Request (0x05)
    Identifier: 0x02
    Length: 4

    0000 00 02 b3 04 e7 76 00 90 8f 03 b5 32 88 64 11 00
    ......v.....2.d..
    0010 00 b2 00 06 c0 21 05 02 00 04 00 02 00 02 b3 04
    ......!..........
    0020 e7 76 00 90 8f 03 b5 32 88 64 11 00 00 b2 00 06
    ..v.....2.d......
    0030 c0 21 05 02 00 04 0d 03 06 11 04 06 .!..........

    No. Time Source Destination
    Protocol Info
    18 72.524730 10.31.2.14 10.31.174.26 PPP LCP
    Termination Ack

    Frame 378 (26 bytes on wire, 26 bytes captured)
    Arrival Time: May 25, 2004 17:56:52.752078000
    Time delta from previous packet: 0.000386000 seconds
    Time since reference or first frame: 72.524730000 seconds
    Frame Number: 378
    Packet Length: 26 bytes
    Capture Length: 26 bytes
    Ethernet II, Src: 00:02:b3:04:e7:76, Dst: 00:90:8f:03:b5:32
    Destination: 00:90:8f:03:b5:32 (10.31.174.26)
    Source: 00:02:b3:04:e7:76 (10.31.2.14)
    Type: PPPoE Session (0x8864)
    PPP-over-Ethernet Session
    Version: 1
    Type: 1
    Code: Session Data
    Session ID: 00b2
    Payload Length: 6
    Point-to-Point Protocol
    Protocol: Link Control Protocol (0xc021)
    PPP Link Control Protocol
    Code: Termination Ack (0x06)
    Identifier: 0x02
    Length: 4

    0000 00 90 8f 03 b5 32 00 02 b3 04 e7 76 88 64 11 00
    ......2.....v.d..
    0010 00 b2 00 06 c0 21 06 02 00 04 .....!....

  2. Re: LCP problem.

    trigerboim@yahoo.com (wd) writes:
    > I'm experiencing a strange problem.
    > In my setup the PPP link is running over PPPoE, and I use windows XP+
    > RASPPPOE to simulate access concentrator and my machine (PPC based,
    > embedded machine) as the client.


    You'll need to check the debug logs on that access concentrator
    (apparently at 00:02:b3:04:e7:76). It seems to have decided to
    restart LCP from scratch, though there's nothing apparent in this log
    that would suggest why it would do that.

    Perhaps it really, really wants MS-CHAPv2 instead of PAP?

    > Can someone shade some light on this behavior?


    Not based on the packet traces, unfortunately. The access server made
    some sort of policy decision, and the reson for it isn't apparent in
    the logs.

    --
    James Carlson, IP Systems Group
    Sun Microsystems / 1 Network Drive 71.234W Vox +1 781 442 2084
    MS UBUR02-212 / Burlington MA 01803-2757 42.497N Fax +1 781 442 1677

  3. Re: LCP problem.

    In article ,
    wd wrote:
    >Hi,
    >I'm experiencing a strange problem.
    >In my setup the PPP link is running over PPPoE, and I use windows XP+
    >RASPPPOE to simulate access concentrator and my machine (PPC based,
    >embedded machine) as the client.
    >
    >During the LCP I negotiate for PAP, MRU & magic number. Now strangely,
    >after the server had negotiated successfully and received
    >configure-ack and the auth process acked by the server as well, it
    >sends conf-request again (immediately! no timeout...)
    >
    >Here is a capture. As you can see in packet 8 the server received
    >conf-ack (the capture was taken on the server machine), packets 9 & 10
    >are the PAP and though there is an authenticate-ack, it sends again
    >conf request in packet 11...
    >
    >Can someone shade some light on this behavior?
    >
    >10x in advance.
    >wd.


    [I've abbreviated the frames below for clarity (as much as that's worth! ;^)]

    Frames from the originator of packet 362 will be labelled A, while frames
    sent back will be labelled B.

    >Frame 362 (60 bytes on wire, 60 bytes captured)
    > Arrival Time: May 25, 2004 17:56:52.588018000
    >Point-to-Point Protocol
    > Protocol: Link Control Protocol (0xc021)
    >PPP Link Control Protocol
    > Code: Configuration Request (0x01)
    > Identifier: 0x00
    > Length: 18
    > Options: (14 bytes)
    > Maximum Receive Unit: 1492
    > Authentication protocol: 4 bytes
    > Authentication protocol: Password Authentication Protocol (0xc023)
    > Magic number: 0x12348765


    A sends LCP Configure-Request to B (note authentication protocol requested).

    >Frame 363 (75 bytes on wire, 75 bytes captured)
    > Arrival Time: May 25, 2004 17:56:52.590713000
    >Point-to-Point Protocol
    > Protocol: Link Control Protocol (0xc021)
    >PPP Link Control Protocol
    > Code: Configuration Request (0x01)
    > Identifier: 0x00
    > Length: 53
    > Options: (49 bytes)
    > Maximum Receive Unit: 1492
    > Authentication protocol: 5 bytes
    > Authentication protocol: Challenge Handshake Authentication Protocol (0xc223)
    > Algorithm: MS-CHAP-2 (0x81)
    > Magic number: 0x278d5720
    > Callback: 3 bytes
    > Operation: Location is determined during CBCP negotiation (0x06)
    > Multilink MRRU: 1614
    > Multilink endpoint discriminator: 23 bytes
    > Class: Locally assigned address (1)
    > Address (20 bytes)
    > Link discriminator for BAP: 0x002d


    B sends LCP Configure-Request to A.

    >Frame 364 (40 bytes on wire, 40 bytes captured)
    > Arrival Time: May 25, 2004 17:56:52.591091000
    >Point-to-Point Protocol
    > Protocol: Link Control Protocol (0xc021)
    >PPP Link Control Protocol
    > Code: Configuration Ack (0x02)
    > Identifier: 0x00
    > Length: 18
    > Options: (14 bytes)
    > Maximum Receive Unit: 1492
    > Authentication protocol: 4 bytes
    > Authentication protocol: Password Authentication Protocol (0xc023)
    > Magic number: 0x12348765


    B sends LCP Configure-Ack to A in response to packet 362.

    >Frame 365 (60 bytes on wire, 60 bytes captured)
    > Arrival Time: May 25, 2004 17:56:52.704754000
    >Point-to-Point Protocol
    > Protocol: Link Control Protocol (0xc021)
    >PPP Link Control Protocol
    > Code: Configuration Reject (0x04)
    > Identifier: 0x00
    > Length: 34
    > Options: (30 bytes)
    > Callback: 3 bytes
    > Operation: Location is determined during CBCP negotiation (0x06)
    > Multilink MRRU: 1614
    > Multilink endpoint discriminator: 23 bytes
    > Class: Locally assigned address (1)
    > Address (20 bytes)


    A sends LCP Configure-Reject to B rejecting several options.

    >Frame 366 (45 bytes on wire, 45 bytes captured)
    > Arrival Time: May 25, 2004 17:56:52.705272000
    >Point-to-Point Protocol
    > Protocol: Link Control Protocol (0xc021)
    >PPP Link Control Protocol
    > Code: Configuration Request (0x01)
    > Identifier: 0x01
    > Length: 23
    > Options: (19 bytes)
    > Maximum Receive Unit: 1492
    > Authentication protocol: 5 bytes
    > Authentication protocol: Challenge Handshake Authentication Protocol (0xc223)
    > Algorithm: MS-CHAP-2 (0x81)
    > Magic number: 0x278d5720
    > Link discriminator for BAP: 0x002d


    B sends new LCP Configure-Request to A without rejected options.

    >Frame 367 (60 bytes on wire, 60 bytes captured)
    > Arrival Time: May 25, 2004 17:56:52.726895000
    >Point-to-Point Protocol
    > Protocol: Link Control Protocol (0xc021)
    >PPP Link Control Protocol
    > Code: Configuration Nak (0x03)
    > Identifier: 0x01
    > Length: 8
    > Options: (4 bytes)
    > Authentication protocol: 4 bytes
    > Authentication protocol: Password Authentication Protocol (0xc023)


    A sends LCP Configure-Nak telling B it doesn't like MSCHAP2 for authentication
    (use PAP instead).

    >Frame 368 (44 bytes on wire, 44 bytes captured)
    > Arrival Time: May 25, 2004 17:56:52.727240000
    >Point-to-Point Protocol
    > Protocol: Link Control Protocol (0xc021)
    >PPP Link Control Protocol
    > Code: Configuration Request (0x01)
    > Identifier: 0x02
    > Length: 22
    > Options: (18 bytes)
    > Maximum Receive Unit: 1492
    > Authentication protocol: 4 bytes
    > Authentication protocol: Password Authentication Protocol (0xc023)
    > Magic number: 0x278d5720
    > Link discriminator for BAP: 0x002d


    B sends LCP Configure-Request to A complying with desired authentication
    protocol (PAP).

    >Frame 369 (60 bytes on wire, 60 bytes captured)
    > Arrival Time: May 25, 2004 17:56:52.739787000
    >Point-to-Point Protocol
    > Protocol: Link Control Protocol (0xc021)
    >PPP Link Control Protocol
    > Code: Configuration Ack (0x02)
    > Identifier: 0x02
    > Length: 22
    > Options: (18 bytes)
    > Maximum Receive Unit: 1492
    > Authentication protocol: 4 bytes
    > Authentication protocol: Password Authentication Protocol (0xc023)
    > Magic number: 0x278d5720
    > Link discriminator for BAP: 0x002d


    A sends LCP Configure-Ack indicating it likes everything.

    At this point, BOTH SIDES have reached the LCP Opened state, and note that
    both sides have agreed to authenticate themselves to the other side with PAP!
    (that is probably an error, but maybe not - who knows??)

    >Frame 370 (60 bytes on wire, 60 bytes captured)
    > Arrival Time: May 25, 2004 17:56:52.739883000
    >Point-to-Point Protocol
    > Protocol: Password Authentication Protocol (0xc023)
    >PPP Password Authentication Protocol
    > Code: Authenticate-Request (0x01)
    > Identifier: 0x01
    > Length: 15
    > Data (11 bytes)
    > Peer ID length: 4 bytes
    > Peer-ID (4 bytes)
    > Password length: 5 bytes
    > Password (5 bytes)


    A sends PAP Authenticate-Request to B with it's peer ID and password.

    >Frame 371 (27 bytes on wire, 27 bytes captured)
    > Arrival Time: May 25, 2004 17:56:52.747269000
    >Point-to-Point Protocol
    > Protocol: Password Authentication Protocol (0xc023)
    >PPP Password Authentication Protocol
    > Code: Authenticate-Ack (0x02)
    > Identifier: 0x01
    > Length: 5
    > Data (1 byte)
    > Message length: 0 bytes


    B sends PAP Authenticate-Ack to A.

    At this point B knows who A is, but A should be waiting to authentication B.

    >Frame 372 (75 bytes on wire, 75 bytes captured)
    > Arrival Time: May 25, 2004 17:56:52.750123000
    >Point-to-Point Protocol
    > Protocol: Link Control Protocol (0xc021)
    >PPP Link Control Protocol
    > Code: Configuration Request (0x01)
    > Identifier: 0x04
    > Length: 53
    > Options: (49 bytes)
    > Maximum Receive Unit: 1492
    > Authentication protocol: 5 bytes
    > Authentication protocol: Challenge Handshake Authentication Protocol (0xc223)
    > Algorithm: MS-CHAP-2 (0x81)
    > Magic number: 0x299714e1
    > Callback: 3 bytes
    > Operation: Location is determined during CBCP negotiation (0x06)
    > Multilink MRRU: 1614
    > Multilink endpoint discriminator: 23 bytes
    > Class: Locally assigned address (1)
    > Address (20 bytes)
    > Link discriminator for BAP: 0x002d


    B sends a NEW LCP Configure-Request to A with a different magic number and
    all the options it originally try to get A to agree to.

    >Frame 373 (60 bytes on wire, 60 bytes captured)
    > Arrival Time: May 25, 2004 17:56:52.750827000
    >Point-to-Point Protocol
    > Protocol: Link Control Protocol (0xc021)
    >PPP Link Control Protocol
    > Code: Configuration Request (0x01)
    > Identifier: 0x01
    > Length: 18
    > Options: (14 bytes)
    > Maximum Receive Unit: 1492
    > Authentication protocol: 4 bytes
    > Authentication protocol: Password Authentication Protocol (0xc023)
    > Magic number: 0x12348765


    Upon receiving an unexpected LCP Configure-Request, A should have taken LCP
    out of the Opened state and restarted LCP negotiations. This starts by A
    sending a new LCP Configure-Request to B.

    >Frame 374 (60 bytes on wire, 60 bytes captured)
    > Arrival Time: May 25, 2004 17:56:52.750871000
    >Point-to-Point Protocol
    > Protocol: Link Control Protocol (0xc021)
    >PPP Link Control Protocol
    > Code: Configuration Reject (0x04)
    > Identifier: 0x04
    > Length: 34
    > Options: (30 bytes)
    > Callback: 3 bytes
    > Operation: Location is determined during CBCP negotiation (0x06)
    > Multilink MRRU: 1614
    > Multilink endpoint discriminator: 23 bytes
    > Class: Locally assigned address (1)
    > Address (20 bytes)


    A sends a new LCP Configure-Reject indicating which options it does not
    like.

    >Frame 375 (30 bytes on wire, 30 bytes captured)
    > Arrival Time: May 25, 2004 17:56:52.751247000
    >Point-to-Point Protocol
    > Protocol: Link Control Protocol (0xc021)
    >PPP Link Control Protocol
    > Code: Configuration Reject (0x04)
    > Identifier: 0x01
    > Length: 8
    > Options: (4 bytes)
    > Authentication protocol: 4 bytes
    > Authentication protocol: Password Authentication Protocol (0xc023)


    For some reason, B sends an LCP Configure-Reject to A about the authentication
    protocol. This may be due to the possibility that B is now a true PPP
    termination point, whereas up until now, B was a local "access concentrator"??

    >Frame 376 (45 bytes on wire, 45 bytes captured)
    > Arrival Time: May 25, 2004 17:56:52.751588000
    >Point-to-Point Protocol
    > Protocol: Link Control Protocol (0xc021)
    >PPP Link Control Protocol
    > Code: Configuration Request (0x01)
    > Identifier: 0x05
    > Length: 23
    > Options: (19 bytes)
    > Maximum Receive Unit: 1492
    > Authentication protocol: 5 bytes
    > Authentication protocol: Challenge Handshake Authentication Protocol (0xc223)
    > Algorithm: MS-CHAP-2 (0x81)
    > Magic number: 0x299714e1
    > Link discriminator for BAP: 0x002d


    B again sends LCP Configure-Request to A after removing rejected options.

    >Frame 377 (60 bytes on wire, 60 bytes captured)
    > Arrival Time: May 25, 2004 17:56:52.751692000
    >Point-to-Point Protocol
    > Protocol: Link Control Protocol (0xc021)
    >PPP Link Control Protocol
    > Code: Termination Request (0x05)
    > Identifier: 0x02
    > Length: 4


    A decides to give up on the connection (probably because B rejected the
    authentication protocol).

    >Frame 378 (26 bytes on wire, 26 bytes captured)
    > Arrival Time: May 25, 2004 17:56:52.752078000
    >Point-to-Point Protocol
    > Protocol: Link Control Protocol (0xc021)
    >PPP Link Control Protocol
    > Code: Termination Ack (0x06)
    > Identifier: 0x02
    > Length: 4


    B agrees to give up on the connection.

    Phew! I think there are a few issues here:

    1) A should (probably) NOT be asking B to autheticate itself.

    2) B should NOT initially agree to autheticate itself if it is indeed
    not willing to authenticate itself.


    I think what is happening is similar to what happens in L2TP where LCP is
    negotiated TWICE; first with the LAC (L2TP access concentrator), and then
    with the LNS (L2TP network server). I think the model allows a single
    LAC to offer services to several LNSs based on the authenticated identity?
    I'm mostly guessing here, since PPPoE is clearly different, but some
    manufacturer may have rolled PPPoE into their L2TP model or something similar??
    The glitch to this theory is that the LAC agreed to authenticate itself,
    and then never did.


    Can you configure the initator stop requesting the peer authenticate themself
    with PAP??

    Patrick
    ========= For LAN/WAN Protocol Analysis, check out PacketView Pro! =========
    Patrick Klos Email: patrick@klos.com
    Klos Technologies, Inc. Web: http://www.klos.com/
    ==================== What goes around, comes around... =====================

  4. Re: LCP problem.

    you were right! problem solved when I configured the client not to requset PAP.

    thank you,
    wd.




    patrick@klos.com wrote in message news:...
    > In article ,
    > wd wrote:
    > >Hi,
    > >I'm experiencing a strange problem.
    > >In my setup the PPP link is running over PPPoE, and I use windows XP+
    > >RASPPPOE to simulate access concentrator and my machine (PPC based,
    > >embedded machine) as the client.
    > >
    > >During the LCP I negotiate for PAP, MRU & magic number. Now strangely,
    > >after the server had negotiated successfully and received
    > >configure-ack and the auth process acked by the server as well, it
    > >sends conf-request again (immediately! no timeout...)
    > >
    > >Here is a capture. As you can see in packet 8 the server received
    > >conf-ack (the capture was taken on the server machine), packets 9 & 10
    > >are the PAP and though there is an authenticate-ack, it sends again
    > >conf request in packet 11...
    > >
    > >Can someone shade some light on this behavior?
    > >
    > >10x in advance.
    > >wd.

    >
    > [I've abbreviated the frames below for clarity (as much as that's worth! ;^)]
    >
    > Frames from the originator of packet 362 will be labelled A, while frames
    > sent back will be labelled B.
    >
    > >Frame 362 (60 bytes on wire, 60 bytes captured)
    > > Arrival Time: May 25, 2004 17:56:52.588018000
    > >Point-to-Point Protocol
    > > Protocol: Link Control Protocol (0xc021)
    > >PPP Link Control Protocol
    > > Code: Configuration Request (0x01)
    > > Identifier: 0x00
    > > Length: 18
    > > Options: (14 bytes)
    > > Maximum Receive Unit: 1492
    > > Authentication protocol: 4 bytes
    > > Authentication protocol: Password Authentication Protocol (0xc023)
    > > Magic number: 0x12348765

    >
    > A sends LCP Configure-Request to B (note authentication protocol requested).
    >
    > >Frame 363 (75 bytes on wire, 75 bytes captured)
    > > Arrival Time: May 25, 2004 17:56:52.590713000
    > >Point-to-Point Protocol
    > > Protocol: Link Control Protocol (0xc021)
    > >PPP Link Control Protocol
    > > Code: Configuration Request (0x01)
    > > Identifier: 0x00
    > > Length: 53
    > > Options: (49 bytes)
    > > Maximum Receive Unit: 1492
    > > Authentication protocol: 5 bytes
    > > Authentication protocol: Challenge Handshake Authentication Protocol (0xc223)
    > > Algorithm: MS-CHAP-2 (0x81)
    > > Magic number: 0x278d5720
    > > Callback: 3 bytes
    > > Operation: Location is determined during CBCP negotiation (0x06)
    > > Multilink MRRU: 1614
    > > Multilink endpoint discriminator: 23 bytes
    > > Class: Locally assigned address (1)
    > > Address (20 bytes)
    > > Link discriminator for BAP: 0x002d

    >
    > B sends LCP Configure-Request to A.
    >
    > >Frame 364 (40 bytes on wire, 40 bytes captured)
    > > Arrival Time: May 25, 2004 17:56:52.591091000
    > >Point-to-Point Protocol
    > > Protocol: Link Control Protocol (0xc021)
    > >PPP Link Control Protocol
    > > Code: Configuration Ack (0x02)
    > > Identifier: 0x00
    > > Length: 18
    > > Options: (14 bytes)
    > > Maximum Receive Unit: 1492
    > > Authentication protocol: 4 bytes
    > > Authentication protocol: Password Authentication Protocol (0xc023)
    > > Magic number: 0x12348765

    >
    > B sends LCP Configure-Ack to A in response to packet 362.
    >
    > >Frame 365 (60 bytes on wire, 60 bytes captured)
    > > Arrival Time: May 25, 2004 17:56:52.704754000
    > >Point-to-Point Protocol
    > > Protocol: Link Control Protocol (0xc021)
    > >PPP Link Control Protocol
    > > Code: Configuration Reject (0x04)
    > > Identifier: 0x00
    > > Length: 34
    > > Options: (30 bytes)
    > > Callback: 3 bytes
    > > Operation: Location is determined during CBCP negotiation (0x06)
    > > Multilink MRRU: 1614
    > > Multilink endpoint discriminator: 23 bytes
    > > Class: Locally assigned address (1)
    > > Address (20 bytes)

    >
    > A sends LCP Configure-Reject to B rejecting several options.
    >
    > >Frame 366 (45 bytes on wire, 45 bytes captured)
    > > Arrival Time: May 25, 2004 17:56:52.705272000
    > >Point-to-Point Protocol
    > > Protocol: Link Control Protocol (0xc021)
    > >PPP Link Control Protocol
    > > Code: Configuration Request (0x01)
    > > Identifier: 0x01
    > > Length: 23
    > > Options: (19 bytes)
    > > Maximum Receive Unit: 1492
    > > Authentication protocol: 5 bytes
    > > Authentication protocol: Challenge Handshake Authentication Protocol (0xc223)
    > > Algorithm: MS-CHAP-2 (0x81)
    > > Magic number: 0x278d5720
    > > Link discriminator for BAP: 0x002d

    >
    > B sends new LCP Configure-Request to A without rejected options.
    >
    > >Frame 367 (60 bytes on wire, 60 bytes captured)
    > > Arrival Time: May 25, 2004 17:56:52.726895000
    > >Point-to-Point Protocol
    > > Protocol: Link Control Protocol (0xc021)
    > >PPP Link Control Protocol
    > > Code: Configuration Nak (0x03)
    > > Identifier: 0x01
    > > Length: 8
    > > Options: (4 bytes)
    > > Authentication protocol: 4 bytes
    > > Authentication protocol: Password Authentication Protocol (0xc023)

    >
    > A sends LCP Configure-Nak telling B it doesn't like MSCHAP2 for authentication
    > (use PAP instead).
    >
    > >Frame 368 (44 bytes on wire, 44 bytes captured)
    > > Arrival Time: May 25, 2004 17:56:52.727240000
    > >Point-to-Point Protocol
    > > Protocol: Link Control Protocol (0xc021)
    > >PPP Link Control Protocol
    > > Code: Configuration Request (0x01)
    > > Identifier: 0x02
    > > Length: 22
    > > Options: (18 bytes)
    > > Maximum Receive Unit: 1492
    > > Authentication protocol: 4 bytes
    > > Authentication protocol: Password Authentication Protocol (0xc023)
    > > Magic number: 0x278d5720
    > > Link discriminator for BAP: 0x002d

    >
    > B sends LCP Configure-Request to A complying with desired authentication
    > protocol (PAP).
    >
    > >Frame 369 (60 bytes on wire, 60 bytes captured)
    > > Arrival Time: May 25, 2004 17:56:52.739787000
    > >Point-to-Point Protocol
    > > Protocol: Link Control Protocol (0xc021)
    > >PPP Link Control Protocol
    > > Code: Configuration Ack (0x02)
    > > Identifier: 0x02
    > > Length: 22
    > > Options: (18 bytes)
    > > Maximum Receive Unit: 1492
    > > Authentication protocol: 4 bytes
    > > Authentication protocol: Password Authentication Protocol (0xc023)
    > > Magic number: 0x278d5720
    > > Link discriminator for BAP: 0x002d

    >
    > A sends LCP Configure-Ack indicating it likes everything.
    >
    > At this point, BOTH SIDES have reached the LCP Opened state, and note that
    > both sides have agreed to authenticate themselves to the other side with PAP!
    > (that is probably an error, but maybe not - who knows??)
    >
    > >Frame 370 (60 bytes on wire, 60 bytes captured)
    > > Arrival Time: May 25, 2004 17:56:52.739883000
    > >Point-to-Point Protocol
    > > Protocol: Password Authentication Protocol (0xc023)
    > >PPP Password Authentication Protocol
    > > Code: Authenticate-Request (0x01)
    > > Identifier: 0x01
    > > Length: 15
    > > Data (11 bytes)
    > > Peer ID length: 4 bytes
    > > Peer-ID (4 bytes)
    > > Password length: 5 bytes
    > > Password (5 bytes)

    >
    > A sends PAP Authenticate-Request to B with it's peer ID and password.
    >
    > >Frame 371 (27 bytes on wire, 27 bytes captured)
    > > Arrival Time: May 25, 2004 17:56:52.747269000
    > >Point-to-Point Protocol
    > > Protocol: Password Authentication Protocol (0xc023)
    > >PPP Password Authentication Protocol
    > > Code: Authenticate-Ack (0x02)
    > > Identifier: 0x01
    > > Length: 5
    > > Data (1 byte)
    > > Message length: 0 bytes

    >
    > B sends PAP Authenticate-Ack to A.
    >
    > At this point B knows who A is, but A should be waiting to authentication B.
    >
    > >Frame 372 (75 bytes on wire, 75 bytes captured)
    > > Arrival Time: May 25, 2004 17:56:52.750123000
    > >Point-to-Point Protocol
    > > Protocol: Link Control Protocol (0xc021)
    > >PPP Link Control Protocol
    > > Code: Configuration Request (0x01)
    > > Identifier: 0x04
    > > Length: 53
    > > Options: (49 bytes)
    > > Maximum Receive Unit: 1492
    > > Authentication protocol: 5 bytes
    > > Authentication protocol: Challenge Handshake Authentication Protocol (0xc223)
    > > Algorithm: MS-CHAP-2 (0x81)
    > > Magic number: 0x299714e1
    > > Callback: 3 bytes
    > > Operation: Location is determined during CBCP negotiation (0x06)
    > > Multilink MRRU: 1614
    > > Multilink endpoint discriminator: 23 bytes
    > > Class: Locally assigned address (1)
    > > Address (20 bytes)
    > > Link discriminator for BAP: 0x002d

    >
    > B sends a NEW LCP Configure-Request to A with a different magic number and
    > all the options it originally try to get A to agree to.
    >
    > >Frame 373 (60 bytes on wire, 60 bytes captured)
    > > Arrival Time: May 25, 2004 17:56:52.750827000
    > >Point-to-Point Protocol
    > > Protocol: Link Control Protocol (0xc021)
    > >PPP Link Control Protocol
    > > Code: Configuration Request (0x01)
    > > Identifier: 0x01
    > > Length: 18
    > > Options: (14 bytes)
    > > Maximum Receive Unit: 1492
    > > Authentication protocol: 4 bytes
    > > Authentication protocol: Password Authentication Protocol (0xc023)
    > > Magic number: 0x12348765

    >
    > Upon receiving an unexpected LCP Configure-Request, A should have taken LCP
    > out of the Opened state and restarted LCP negotiations. This starts by A
    > sending a new LCP Configure-Request to B.
    >
    > >Frame 374 (60 bytes on wire, 60 bytes captured)
    > > Arrival Time: May 25, 2004 17:56:52.750871000
    > >Point-to-Point Protocol
    > > Protocol: Link Control Protocol (0xc021)
    > >PPP Link Control Protocol
    > > Code: Configuration Reject (0x04)
    > > Identifier: 0x04
    > > Length: 34
    > > Options: (30 bytes)
    > > Callback: 3 bytes
    > > Operation: Location is determined during CBCP negotiation (0x06)
    > > Multilink MRRU: 1614
    > > Multilink endpoint discriminator: 23 bytes
    > > Class: Locally assigned address (1)
    > > Address (20 bytes)

    >
    > A sends a new LCP Configure-Reject indicating which options it does not
    > like.
    >
    > >Frame 375 (30 bytes on wire, 30 bytes captured)
    > > Arrival Time: May 25, 2004 17:56:52.751247000
    > >Point-to-Point Protocol
    > > Protocol: Link Control Protocol (0xc021)
    > >PPP Link Control Protocol
    > > Code: Configuration Reject (0x04)
    > > Identifier: 0x01
    > > Length: 8
    > > Options: (4 bytes)
    > > Authentication protocol: 4 bytes
    > > Authentication protocol: Password Authentication Protocol (0xc023)

    >
    > For some reason, B sends an LCP Configure-Reject to A about the authentication
    > protocol. This may be due to the possibility that B is now a true PPP
    > termination point, whereas up until now, B was a local "access concentrator"??
    >
    > >Frame 376 (45 bytes on wire, 45 bytes captured)
    > > Arrival Time: May 25, 2004 17:56:52.751588000
    > >Point-to-Point Protocol
    > > Protocol: Link Control Protocol (0xc021)
    > >PPP Link Control Protocol
    > > Code: Configuration Request (0x01)
    > > Identifier: 0x05
    > > Length: 23
    > > Options: (19 bytes)
    > > Maximum Receive Unit: 1492
    > > Authentication protocol: 5 bytes
    > > Authentication protocol: Challenge Handshake Authentication Protocol (0xc223)
    > > Algorithm: MS-CHAP-2 (0x81)
    > > Magic number: 0x299714e1
    > > Link discriminator for BAP: 0x002d

    >
    > B again sends LCP Configure-Request to A after removing rejected options.
    >
    > >Frame 377 (60 bytes on wire, 60 bytes captured)
    > > Arrival Time: May 25, 2004 17:56:52.751692000
    > >Point-to-Point Protocol
    > > Protocol: Link Control Protocol (0xc021)
    > >PPP Link Control Protocol
    > > Code: Termination Request (0x05)
    > > Identifier: 0x02
    > > Length: 4

    >
    > A decides to give up on the connection (probably because B rejected the
    > authentication protocol).
    >
    > >Frame 378 (26 bytes on wire, 26 bytes captured)
    > > Arrival Time: May 25, 2004 17:56:52.752078000
    > >Point-to-Point Protocol
    > > Protocol: Link Control Protocol (0xc021)
    > >PPP Link Control Protocol
    > > Code: Termination Ack (0x06)
    > > Identifier: 0x02
    > > Length: 4

    >
    > B agrees to give up on the connection.
    >
    > Phew! I think there are a few issues here:
    >
    > 1) A should (probably) NOT be asking B to autheticate itself.
    >
    > 2) B should NOT initially agree to autheticate itself if it is indeed
    > not willing to authenticate itself.
    >
    >
    > I think what is happening is similar to what happens in L2TP where LCP is
    > negotiated TWICE; first with the LAC (L2TP access concentrator), and then
    > with the LNS (L2TP network server). I think the model allows a single
    > LAC to offer services to several LNSs based on the authenticated identity?
    > I'm mostly guessing here, since PPPoE is clearly different, but some
    > manufacturer may have rolled PPPoE into their L2TP model or something similar??
    > The glitch to this theory is that the LAC agreed to authenticate itself,
    > and then never did.
    >

    >
    > Can you configure the initator stop requesting the peer authenticate themself
    > with PAP??
    >
    > Patrick
    > ========= For LAN/WAN Protocol Analysis, check out PacketView Pro! =========
    > Patrick Klos Email: patrick@klos.com
    > Klos Technologies, Inc. Web: http://www.klos.com/
    > ==================== What goes around, comes around... =====================


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