\documentclass[a4paper,french,12pt]{article}

\title{Networks and Protocols --- Wireshark Lab}
\author{Tunui Franken}

\usepackage{../cours}

\begin{document}

\maketitle
\clearpage

\section{HTTP}

    \subsection{Basic HTTP GET/response interaction}

        \begin{enumerate}

            \item Is your browser running HTTP version 1.0 or 1.1?
                What version of HTTP is the server running?

                The client and the server are both running HTTP version 1.1.
                (client: trace n°10, server: trace n°12)

            \item What languages (if any) does your browser indicate that it cas accept to the server?

                The \texttt{Accept-Language} header indicates that the browser accepts \texttt{en-us}.

            \item What is the IP address of your computer?
                Of the gaia.cs.umass.edu server?

                The client computer has private address 192.168.1.102.
                The server has address 128.119.245.12.

            \item What is the status code returned from the server to your browser?

                The GET ``ok'' response indicates a 200 status code.

            \item When was the HTML file that you are retrieving last modified at the server?

                The \texttt{Last-Modified} header indicates \texttt{Tue, 23 Sep 2003 05:29:00 GMT}.

            \item How many bytes of content are being returned to your browser?

                The server has returned 73 bytes.

        \end{enumerate}

    \subsection{HTTP conditional GET/response interaction}

        \begin{enumerate}\setcounter{enumi}{6}

            \item Inspect the contents of the first HTTP GET request from your browser to the server.
                Do you see an ``IF-MODIFIED-SINCE'' line in the HTTP GET\@?

                The line is not present.

            \item Inspect the contents of the server response.
                Did the server explicitly return the contents of the file?
                How can you tell?

                The server returned a 200 return status code.
                If it hadn't explicitly returned the contents of the file, it would have returned a 304 status code.

            \item Now inspect the contents of the second HTTP GET request from your browser to the server.
                Do you see an ``IF-MODIFIED-SINCE'' line in the HTTP GET\@?
                If so, what information follows the ``IF-MODIFIED-SINCE'' header?

                This time, the header is present in the browser's request.
                The next header is ``IF-NONE-MATCH''.

            \item What is the HTTP status code and phrase returned from the server in response to this second HTTP GET\@?
                Did the server explicitly return the contents of the file?

                This time the response has a 304 return status code, with a ``Not Modified'' message.
                The server does not send the file contents, because the browser has already cached it.

        \end{enumerate}

    \subsection{Retrieving long documents}

        \begin{enumerate}\setcounter{enumi}{10}

            \item How many HTTP GET request messages did your browser send?
                Which packet number in the trace contains the GET message for the Bill of Rights?

                The browser has sent one GET request.
                This request has packet number 8.

            \item Which packet number in the trace contains the status code and phrase associated with the response to the HTTP GET response?

                The packet n°14 contains the status code and phrase.

            \item What is the status code and phrase in the response?

                The status code returned by the server is 200, associated with the ``OK'' phrase.

            \item How many data-containing TCP segments were needed to carry the single HTTP response and the the text of the Bill of Rights?

                The HTTP response was broken down into 3 separate TCP segments containing data.
                Each segment being 1460 bytes long, they add up to 4272.

        \end{enumerate}

    \subsection{HTML Documents with Embedded Objects}

        \begin{enumerate}\setcounter{enumi}{14}

            \item How many HTTP GET request messages did your browser send?
                To which Internet addesses were these GET requests sent?

                The browser has sent 3 GET request messages to 3 different IP addresses~:
                \texttt{128.119.245.12}, \texttt{165.193.123.218} and \texttt{134.241.6.82}.

            \item Can you tell whether your browser downloaded the two images serially, or whether they were downloaded from the two web sites in parallel?
                Explain.

                The \texttt{Time} column indicates that the GET requests were made separately.
                The TCP data indicates the the Acknowledgement numbers are also independant (their relative value is 1).

        \end{enumerate}

    \subsection{HTTP Authentication}

\section{DNS}

\end{document}
