["Velissarios Lataris" <Velissarios.Lataris@xxxxxxxxxxxxxx>]

Hi all,

 

First time I write in the list, nice to meet you all. Here’s my question:

 

In a series of ftp data (over a wireless link and using the huawei e220 device) I see the following Fragmented IP packet (details are below) that I can’t understand.

 

Many things are wrong with this one:

 

First of all it shouldn’t be in this sequence, its source/destination addresses are unknown, all its fields are messed up e.g. protocol unknown, IPv12???, IP header 60bytes???, diffserv is true, all the checksums are bad and the list goes on…

 

Could it be that I captured something that wasn’t meant for me due to bad radio conditions? Why are its fields so messed up? Any help on what happened here would be really appreciated!

 

Thanks

Velissarios

 

No.                   Time                             Source                Destination                  Protocol Info

5860     09:43:43.517578            10.32.8.127                   195.5.122.37                 FTP-DATA FTP Data: 1460 bytes

5861     09:43:43.689453            204.123.41.219              65.31.115.189                IP       Fragmented IP protocol (proto=Unknown 0xfc, off=920)

5862     09:43:43.798828            10.32.8.127                   195.5.122.37                 FTP-DATA FTP Data: 1460 bytes

 

Frame 5861 (78 bytes on wire, 78 bytes captured)

    Arrival Time: Apr  4, 2008 09:43:43.689453000

    [Time delta from previous packet: 0.171875000 seconds]

    [Time since reference or first frame: 200.359375000 seconds]

    Frame Number: 5861

    Packet Length: 78 bytes

    Capture Length: 78 bytes

    [Frame is marked: False]

    [Protocols in frame: eth:ip:data]

    [Coloring Rule Name: Checksum Errors]

    [Coloring Rule String: cdp.checksum_bad==1 || edp.checksum_bad==1 || ip.checksum_bad==1 || tcp.checksum_bad==1 || udp.checksum_bad==1]

Ethernet II, Src: b6:de:20:00:0a:00 (b6:de:20:00:0a:00), Dst: 0a:00:0a:00:00:00 (0a:00:0a:00:00:00)

    Destination: 0a:00:0a:00:00:00 (0a:00:0a:00:00:00)

        Address: 0a:00:0a:00:00:00 (0a:00:0a:00:00:00)

        .... ...0 .... .... .... .... = IG bit: Individual address (unicast)

        .... ..1. .... .... .... .... = LG bit: Locally administered address (this is NOT the factory default)

    Source: b6:de:20:00:0a:00 (b6:de:20:00:0a:00)

        Address: b6:de:20:00:0a:00 (b6:de:20:00:0a:00)

        .... ...0 .... .... .... .... = IG bit: Individual address (unicast)

        .... ..1. .... .... .... .... = LG bit: Locally administered address (this is NOT the factory default)

    Type: IP (0x0800)

Internet Protocol, Src: 204.123.41.219 (204.123.41.219), Dst: 65.31.115.189 (65.31.115.189)

    Version: 12

    Header length: 60 bytes

    Differentiated Services Field: 0x69 (DSCP 0x1a: Assured Forwarding 31; ECN: 0x01)

        0110 10.. = Differentiated Services Codepoint: Assured Forwarding 31 (0x1a)

        .... ..0. = ECN-Capable Transport (ECT): 0

        .... ...1 = ECN-CE: 1

    Total Length: 59586

    Identification: 0xdf43 (57155)

    Flags: 0x0e (Don't Fragment) (More Fragments)

        1... = Reserved bit: Set

        .1.. = Don't fragment: Set

        ..1. = More fragments: Set

    Fragment offset: 920

    Time to live: 243

    Protocol: Unknown (0xfc)

    Header checksum: 0x70d0 [incorrect, should be 0x60b5]

        [Good: False]

        [Bad : True]

    Source: 204.123.41.219 (204.123.41.219)

    Destination: 65.31.115.189 (65.31.115.189)

    Options: (40 bytes)

        Unknown (0x49) (option length = 155 bytes says option goes past end of options)

Data (4 bytes)

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