Wireshark · Ethereal-dev: [Ethereal-dev] distinguishing multiple files in email and FTP.

["Srivathsan_Srinivasagopalan" <Srivathsan_Srinivasagopalan@xxxxxxxxxx>]

Hi,

    I would like to know how SMTP (or any email application like Outlook) and FTP provides information about clearly distinguishing between different files which are attached and emailed at once (or FTP’ed at once using mget *).

 

I am monitoring the incoming packets and doing deep-packet processing by reading the headers upto application layer. Suppose I attach 10 files (word, pdf, xls, txt etc) to an email, I would like to know when the first file is completely received, when the second file is completely received and so on. What kind of control messages or fields in the protocol should I be watching to know the end of a **SINGLE** file transfer?

 

NOTE: I am just watching the traffic. I am neither the client nor the server. I would be watching **ALL** the traffic (control and data) between the client and server.

 

I think SMTP really doesn't care about the files being attached. It takes all of them in binary format and sees them as a payload. But, there must be a way to clearly distinguish the end of each files being attached. I think such facility is provided by the individual email-clients.

 

Please let me know the answer for the same if I use FTP.

 

Any help is appreciated.

 

Thanks,

Sri.

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