Apolgies,

I set my message settings to digest so I didn't get the individual mail to  
reply to.  Can you reply to your message on the board and so I'll now  
receive it in my mail and a single mail (rather than part of the digest, I  
new to mailing lists like this, sorry!)?

Anyway yes that helps in so far as it gets rid of all non-HTTP packets but  
there are times when I need the TCP packets.  I'm not entirely sure if I  
need each one or just the ones that come as part of the standard protocol  
packets (POP, HTTP etc).  In this app I parse instant messages, email (web  
and pop) and http stuff.  I'll investigate my code base and figure out if  
I reall do need to those single tcp packets (quite probable I don't).

Thanks,
JP

On Thu, 23 Oct 2008 12:54:20 +0100, John Paul Sheridan  
<[EMAIL PROTECTED]> wrote:

> Hi all,
>
> First time post.
>
> I'm developing a java based app that uses tshark as the underlying  
> capture mechanism.  I set up tshark and set capture filters and output  
> the data in PDML format (which is captured via stdin in my Java app and  
> parsed via SAX).
>
> I've created a stream manager that holds stream objects.  Each stream  
> contains all packets belonging to the communication between a client and  
> server i.e. each packet sent between the client/server for any one TCP  
> Stream.
>
> For the purpose of this mail I'm targetting HTTP.
>
> I capture all TCP packets and add them to the appropriate stream.  When  
> I come across a HTTP message I add this to the same stream.  In my  
> capture file that I use for testing I have HTTP request and HTTP  
> response.  So the first 3 packets are those of the TCP handshake (SYN,  
> SYN_ACK and ACK).  The fourth packet would normally be the HTTP request  
> but due to the fact the segments are split up and then reassembled I  
> actually have four extra TCP packets that I don't need (yes I know they  
> are needed but I only want the reassembled one). Here are some packet  
> details
>
> Handshake
> ---------
> 1. SYN from Client
> 2. SYN_ACK from Server
> 3. ACK from Client
>
> Extra packets
> -------------
> 4. RST_ACK from Client
> 5. ACK from Client (TCP segment of a reassembled PDU)
> 6. ACK from Client (TCP segment of a reassembled PDU)
> 7. PSH_ACK from Client (TCP segment of a reassembled PDU)
>
> HTTP Request
> ------------
> 8. PSH_ACK HTTP Request from Client (POST method)
>
>  From what I understand that PDUs can be split across segments for two  
> main reasons:
> 1. Some packets are missing (not in my case)
> 2. Size of info based on segment means it has to be split
>
> I need the fact wireshark can reassemble the data into another packet so  
> I'm not willing to turn reassembly off.
>
> I dont want to see the extra TCP segment packets in my PDML stream, only  
> the reassembled ones.  Is there a filter (capture or display) that I can  
> set with t-shark to omit the segment packets from my PDML stream  
> (remember I use Wireshark for visual analysis of the data but tshark in  
> my java app?
>
> Thanks in advance,
> JP
>



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