1.1 --- a/thesis/tex/1-Introduction.tex	Thu Jan 15 12:07:06 2009 +0100
     1.2 +++ b/thesis/tex/1-Introduction.tex	Thu Jan 15 12:08:32 2009 +0100
     1.3 @@ -19,14 +19,16 @@
     1.4  
     1.5  This thesis will frequently use the three terms: \MTA, \NAME{MUA}, and \NAME{MDA}. The name the three different kinds of software that are the nodes of the email infrastructure. Here they are explained with references to the snail mail system which is known from everyday's life. Figure \ref{fig:mail-agents} shows the relation between those three mail agents and the way an email message takes trough the system.
     1.6  
     1.7 -\paragraph{MTA}
     1.8 +\begin{description}
     1.9 +\item[\MTA:]
    1.10  \name{Mail Tranfer Agents} are the post offices for electronic mail. The basic job of an \MTA\ is to transport mail from senders to recipients, or more pedantic: from \MTA\ to \MTA. \sendmail, \exim, \qmail, \postfix, and of course \masqmail\ are \MTA{}s. \MTA{}s are explained in more detail in chapter \ref{chap:mail-transfer-agents}.
    1.11  
    1.12 -\paragraph{MUA}
    1.13 +\item[\NAME{MUA}:]
    1.14  \name{Mail User Agents} are the software the user deals with. He writes and reads email with it. The \NAME{MUA} passes outgoing mail to the nearest \MTA. Also the \NAME{MUA} displays the contents of the user's mailbox. Well known \NAME{MUA}s are \name{Mozilla Thunderbird} and \name{mutt} on \unix\ systems, and \name{Microsoft Outlook} on \name{Windows}.
    1.15  
    1.16 -\paragraph{MDA}
    1.17 +\item[\NAME{MDA}:]
    1.18  \name{Mail Delivery Agents} correspond to postmen in the real world. They receive mail, destinated to recipients they are responsible for, from an \MTA, and deliver it to the mailboxes of those recipients. Many \MTA{}s include an own \NAME{MDA}, but specialized ones exist: \name{procmail} and \name{maildrop} are examples.
    1.19 +\end{description}
    1.20  
    1.21  \begin{figure}
    1.22  	\begin{center}
    1.23 @@ -65,10 +67,7 @@
    1.24  
    1.25  Following is a sample mail message with four header lines (\texttt{From:}, \texttt{To:}, \texttt{Date:}, and \texttt{Subject:}) and three lines of message body.
    1.26  
    1.27 -\begin{quote}
    1.28 -\footnotesize
    1.29 -\input{input/sample-email.txt}
    1.30 -\end{quote}
    1.31 +\codeinput{input/sample-email.txt}
    1.32  
    1.33  Email messages are put into envelopes for transfer. This concept is derived from the real world, so it is easy to understand. The envelope is used to route the message from sender to recipient. It contains the sender's address and addresses of one or more recipients. Envelopes are generated by \MTA{}s, usually by using mail header data. The user has not to deal with them.
    1.34  
    1.35 @@ -124,16 +123,7 @@
    1.36  
    1.37  \subsubsection*{Typical usage scenarios}
    1.38  
    1.39 -This section describes two common setups that makes senseful use of \masqmail. They are shown in figure \ref{fig:masqmail-typical-usage}.
    1.40 -
    1.41 -\paragraph{Scenario 1}
    1.42 -Imagine a home network consisting of some workstations without a server. The network is connected to the Internet.
    1.43 -
    1.44 -Every workstation would be equiped with \masqmail. Mail transfer within the same machine or within the local net works straight forward using direkt transfer. Outgoing mail to the internet is sent, to an \name{Internet Service Provider} (short: \NAME{ISP}) for relaying whenever the router goes online. The configuration of \masqmail\ would be the same on every computer, except different hostnames.
    1.45 -To receive mail from the Internet requires a mailbox on the \NAME{ISP}'s mail server. Mail needs to be fetched from the \NAME{ISP}'s server onto the workstation. % pop3/imap
    1.46 -
    1.47 -\paragraph{Scenario 2}
    1.48 -In the same network but with a server, one could have \masqmail\ running on the server and using simple forwarders (see \ref{subsec:relay-only}) on the workstations to tranfer mail to the server. The server would then, dependent on the desination of the message, deliver locally or relay to an \NAME{ISP}'s server for further relay. This setup does only support mail transfer to the server, but not back to a workstation. However, it can be solved by mounting the users mailbox from the server to the workstation, or by making the workstations fetch mail from the server. % pop3/imap
    1.49 +This section describes three common setups that makes senseful use of \masqmail. The first two are shown in figure \ref{fig:masqmail-typical-usage}.
    1.50  
    1.51  \begin{figure}
    1.52  	\begin{center}
    1.53 @@ -143,10 +133,23 @@
    1.54  	\label{fig:masqmail-typical-usage}
    1.55  \end{figure}
    1.56  
    1.57 -%fixme: what about notebooks?
    1.58 -<< notebooks >>
    1.59 +Imagine a home network consisting of some workstations which is connected to the Internet.
    1.60  
    1.61 -In general, all kinds of usage scenarios within a trusted network are possible. Important to notice is that mail can not be send from outside into the local network. This limitation leads to the next section.
    1.62 +\begin{description}
    1.63 +\item[Scenario 1:]
    1.64 +If no server is present, every workstation would be equiped with \masqmail. Mail transfer within the same machine or within the local net works straight forward using direkt transfer. Outgoing mail to the internet is sent, to an \name{Internet Service Provider} (short: \NAME{ISP}) for relaying whenever the router goes online. The configuration of \masqmail\ would be the same on every computer, except different hostnames.
    1.65 +To receive mail from the Internet requires a mailbox on the \NAME{ISP}'s mail server. Mail needs to be fetched from the \NAME{ISP}'s server onto the workstation using the \NAME{POP3} or \NAME{IMAP} protocol.
    1.66 +
    1.67 +\item[Scenario 2:]
    1.68 +In the same network but with a server, one could have \masqmail\ running on the server and using simple forwarders (see \ref{subsec:relay-only}) on the workstations to tranfer mail to the server. The server would then, dependent on the desination of the message, deliver locally or relay to an \NAME{ISP}'s server for further relay. This setup does only support mail transfer to the server, but not back to a workstation. However, it can be solved by mounting the users mailbox from the server to the workstation, or by using the \NAME{POP3} or \NAME{IMAP} protocol to fetch the mail in the server's mailbox from the workstations. Mail transfer from the \NAME{ISP} to the local server needs \NAME{POP3} or \NAME{IMAP} as well.
    1.69 +
    1.70 +\item[Scenario 3:]
    1.71 +A third scenario is unrelated as it is about notebooks. Notebooks are usually used as mobile workstations. One uses them to work at different locations. With the increasing popularity of wireless networks this gets more and more common. Different networks have different setups: In one network it is best to send mail to an \NAME{ISP} for relay. In another network it might be prefered to use a local mail server. A third network may have no Internet access at all, hence using a local mail server is required. All these different setups can be configured once and then used by simply telling the online state to \masqmail, even automatically within a network setup script.
    1.72 +\end{description}
    1.73 +
    1.74 +
    1.75 +
    1.76 +In general, all kinds of usage scenarios within a trusted network are possible. Important to notice is that mail can not be send from outside into the trusted network then. For using \masqmail\ on notebooks it is suggested to only accept mail from local users, because notebooks are often in untrusted environments. This limitation leads to the next section.
    1.77  
    1.78  
    1.79  
    1.80 @@ -162,9 +165,9 @@
    1.81  \hfill\citeweb{masqmail:homepage2}
    1.82  \end{quote}
    1.83  
    1.84 -The actual problem is not the permanent Internet connection, but listening for incomming mail on it. If a firewall is closed for incoming mail, then the permanent Internet connection is no problem.
    1.85 +The actual problem is not the permanent Internet connection, but listening for incomming mail on it. If a firewall is closed for incoming mail, then the permanent Internet connection is no problem. \masqmail\ should not be used for permanent internet connections. Or at least it needs to be secured with care.
    1.86  
    1.87 -Hence, \masqmail\ should not be used for permanent internet connections. Or at least it needs to be secured with care.
    1.88 +The Internet is the common example for an untrusted network, but this applies to any other untrusted network too.
    1.89  
    1.90  
    1.91