On Jan 21, 2010, at 11:08 AM, Eddie wrote:
> LAN IP headers:
>
> 45
Version/IHL - version 4, 20 bytes.
> 00
Type of Service
> 05 14
Total length - 1300 bytes (1280 bytes of IP payload)
> 05 d7
Identification - 0x05d7
> 20 00
Flags and Fragment Offset: More Fragments, fragment offset = 0
> 80
Time to Live
> 11
Protocol - 17=UDP
> f3 f9
Header Checksum
> c0 a8 00 1e
Source Address
> 0010 ab a1 af a0
Destination Address
> 0000 45
Version/IHL
> 00
Type of Service
> 03 c0
Total length - 960 bytes (940 bytes of IP payload)
> 05 d7
Identification - 0x05d7, same as the previous fragment (which is as it should be)
> 00 a0
Flags and Fragment Offset: fragment offset=160=160*8 bytes=1280 bytes (which is as it should be, as that's the length of the previous fragment's payload)
> 80
Time to Live
> 11
Protocol - 17=UDP
> 14 ae
Header Checksum
> c0 a8 00 1e
Source Address - same as the previous fragment (which is as it should be)
> 0010 ab a1 af a0
Destination Address - same as the previous fragment (which is as it should be)
> WAN IP headers
>
> 45
Version/IHL
> 00
Type of Service
> 05 dc
Total length - 1500 bytes (1480 bytes of IP payload)
> 36 98
Identification - 0x3698
> 20 00
Flags and Fragment Offset: More Fragments, fragment offset = 0
> 7f
Time to Live
> 11
Protocol - 17=UDP
> a7 46
Header Checksum
> 62 94 7a 5c
Source Address
> ab a1 af a0
Destination Address
> 45
Version/IHL
> 00
Type of Service
> 02 f8
Total length - 760 bytes (740 bytes of IP payload)
> 36 98
Identification - 0x3698, same as the previous fragment (which is as it should be)
> 00 b9
Flags and Fragment Offset: fragment offset = 185=185*8 bytes=1480 bytes (which is as it should be, as that's the length of the previous fragment's payload)
> 7f
Time to Live
> 11
Protocol - 17=UDP
> c9 71
Header Checksum
> 62 94 7a 5c
Source Address - same as the previous fragment (which is as it should be)
> ab a1 af a0
Destination Address - same as the previous fragment (which is as it should be)
There isn't anything obvious that should cause Wireshark not to attempt reassembly, but I didn't check the IP header checksum - is Wireshark reporting IP checksum errors on any of the WAN packets?
Can you save just the two offending fragments from the WAN capture to a file? If so, when you read the file in, does it reassemble the fragments? If not, could you send us that capture, along with the version information from Wireshark?
> Is there a way to grab the interpreted version of these.
Not with copy/paste, unfortunately. You could use File->Export to export the dissected version of the packets as text.
