--- a/thesis/tex/1-Candidates.tex	Sun Oct 19 17:58:41 2008 +0200
+++ b/thesis/tex/1-Candidates.tex	Sun Oct 19 18:00:01 2008 +0200
@@ -1,8 +1,10 @@
 \chapter{\unix\ \MTA{}s}
 
 This chapter introduces a group of \mta{}s.
-These will be presented to the reader in a short overview and with the most important facts.
-The next chapter will show a comparison of the candidates in several disciplines.
+The selected group will be delimited against other groups of \MTA{}s, which are described as well.
+
+The chosen programs will be presented to the reader in a short overview and with the most important facts.
+The next chapter will show a comparison of these programs in several disciplines.
 
 
 \section{Types of \MTA{}s}
@@ -16,32 +18,44 @@
 Others have have every feature you can think of.
 And maybe there are some that do nothing else, but transporting email.
 
+Here are groups of \mta{}s that will not be regarded in the following chapter.
+% Prof: briefly discuss the border between small MTAs (sendmail, masqmail) and state-of-the-art mailservers (postfix) and groupware (notes, exchange): give usecases.
 
-\section{The ones not regarded here}
-The candidates for the competition in the next chapter are a subset of the \MTA{}s available.
-Comparision between totally different programs (apart of one function) makes not much sense.
-One would not use a program for a job it is not suited for.
-Therefor \mta{}s that are rarely similar to \masqmail\ are not regarded.
+\subsection{Relay-only \MTA{}s}
+This is the most simple kind of \MTA. They transfer mail only to defined \name{smart hosts}\footnote{\name{smart host}s are \MTA{}s that receives email and route it to the actual destination}. \name{Relay-only} \MTA{}s do not receive mail, they only send it.
+
+Most \MTA{}s can be configured to act as such a forwarder. But this is usually an additional functionality.
+
+One would use such a program to give a system the possibility to send mail, without the need to do lots of configuration. In a local network, usually the clients are set up with such a forwarder, while there is one \name{mail server} that acts as a \name{smart host}. The ``dumb'' clients send mail only to this one \name{mail server} which does the ``real work''.
 
-The first group of programs to sort out are the so called \name{groupware} programs.
-These provide a whole lot of functions, including mail transfer, file storage, calendars, resource management, instant messaging and more.
+Examples for that group are: \name{nullmailer}, \name{ssmtp} and \name{esmtp}.
+
+
+\subsection{Groupware}
+Normally the term ``groupware'' does not mean one single program, but a suite of programs. They are build up a framework which can be populated with various modules that provide actual funktionality. These modules including mail transfer, file storage, calendars, resource management, instant messaging and more.
+
+One would use one of these program suites if the main work to do is not mail transfer, but providing communication and team working support for a group of people. The most common scenario are companies. They have \name{groupware} running to provide adequate services for their teams to work efficently. But home servers may provide \name{groupware} services for the family members also.
+
 Examples for this kind of programs are: \name{Lotus Notes}, \name{Microsoft Exchange}, \name{OpenGroupware.org} and \name{eGroupWare}.
 
-The second group are the \name{relay-only} \MTA{}s.
-They transfer mail only to defined \name{smart hosts}\index{smart host}\footnote{\MTA{}s that receives email and route it to the actual destination}.
-Most \MTA{}s can be configured to act as such a forwarder.
-But this is normally an additional functionality.
-Examples for that group are: \name{nullmailer}, \name{ssmtp} and \name{esmtp}.
 
+\subsection{More limitations}
 Third, only \emph{sendmail-compatible} \MTA{}s will be regarded in the competition.
-Hence all \MTA{}s not having a \emph{sendmail-compatible} interface or not offering it as a compatibility addon, will not be covered here.
+Hence all \MTA{}s not having a \emph{sendmail-compatible} interface or not offering it as a compatibility addon, will not be covered here. %FIXME: give an example for non-sendmail-compatible
 The reason is the heavy reliance of \unix\ systems on the existance of a programs called \path{sendmail}.
 This has historical reasons. See section \ref{sec:sendmail} for further information.
 
 Further more, only programs with source code available are regarded. %FIXME: why
 
 
-\section{The competitors}
+\subsection{The ones not regarded here}
+The candidates for the competition in the next chapter are a subset of the \MTA{}s available.
+Comparision between totally different programs (apart of one function) makes not much sense. %FIXME: better words
+One would not use a program for a job it is not suited for.
+Therefor \mta{}s that are rarely similar to \masqmail\ are not regarded.
+
+
+\section{The programs regarded}
 The programs remaining are \emph{sendmail-compatible} ``smart'' \MTA{}s that do not offer masses of features unrelated to mail transport.
 
 For the comparision, five programs of this group are taken.
@@ -52,9 +66,6 @@
 Other, but not covered, group members are: %FIXME:  are these all MTAs of that group? why these and not others?
 %TODO: what about `courier-mta'?
 
-% http://www.yolinux.com/TUTORIALS/LinuxTutorialMailMTA.html
-% http://homepages.tesco.net/~J.deBoynePollard/Reviews/UnixMTSes/
-
 Here follows a small introduction to each of the five.
 
 \subsection{\sendmail}
@@ -69,10 +80,11 @@
 \sendmail\ is focused on transfering mails between different protocols and networks, this lead to a very flexible (though complex) configuration.
 
 The latest version is 8.14.3 from May 2008.
+The program is distributed under the \name{Sendmail License} as both, \freesw\ and proprietary software of \name{Sendmail, Inc.}.
+
 Further development will go into the project \name{MeTA1} which succeeds \sendmail.
 
 More information can be found on the \sendmail\ homepage \citeweb{sendmail:homepage} and on \citeweb{wikipedia:sendmail} and \citeweb{jdebp}.
-%FIXME: license
 
 
 \subsection{\name{qmail}}
@@ -89,18 +101,48 @@
 
 
 \subsection{\name{postfix}}
-%TODO: author, date of first release, basic intention of program, ...
-%TODO: references to various descriptions
+The \name{postfix} project was started in 1999 at \name{IBM research}, then called \name{VMailer} or \name{IBM Secure Mailer}.
+Wietse Venema's program ``attempts to be fast, easy to administer, and secure. The outside has a definite Sendmail-ish flavor, but the inside is completely different.''\citeweb{postfix:homepage}
+In fact, \name{postfix} was mainly designed after qmail's architecture to gain security.
+But in contrast to \name{qmail} it aims much more on being fast and full-featured.
+
+Today \name{postfix} is taken by many \unix systems and \gnulinux distributions as default \MTA.
+
+The latest stable version is numbered 2.5.5 from August 2008.
+\name{postfix} is covered by the \name{IBM Public License 1.0} which is a \freesw\ license.
+
+Additional information is available on the program's homepage \citeweb{postfix:homepage}, on \citeweb{jdebp} and \citeweb{wikipedia:postfix}.
+
 
 \subsection{\name{exim}}
-%TODO: author, date of first release, basic intention of program, ...
-%TODO: references to various descriptions
+\name{exim} was started in 1995 by Philip Hazel at the \name{University of Cambridge}.
+Its age is about the same as \name{qmail}'s, but the architecture is totally different.
+
+While \name{qmail} took a completely new approach, \name{exim} forked of \name{smail-3}, and therefor is monolitic like that and like \sendmail.
+But having no separation of the individual components of the system, like \name{qmail} and \name{postfix} have, did not hurt.
+Its security is comparably good.
+
+\name{exim} is highly configurable, especially in the field of mail policies.
+This makes it easy to specify how mail is routed through the system and who is allowed to send email to whom.
+Also interfaces for integration of virus and spam check programs are provided by design.
+
+The program is \freesw, released under the \GPL. The latest stable version is 4.69 from December 2007.
+
+One finds \name{exim} on its homepage \citeweb{exim:homepage}. More information about it can be retrieved from \citeweb{wikipedia:exim} and \citeweb{jdebp}.
+
 
 \subsection{\masqmail}
 The \masqmail\ program was written by Oliver Kurth, starting in 1999.
-His aim was to create a \mta\ which is especially focused on computers with dial-up connections to the internet.
-\masqmail\ handles situations which are rarely solveable with the common \MTA{}s.
-%TODO: references to various descriptions
+His aim was to create a small \mta\ which is especially focused on computers with dial-up connections to the internet.
+\masqmail\ is easy configurable for situations which are rarely solveable with the common \MTA{}s.
+
+\masqmail\ queues mail for destinations outside the local network if no connection to the internet is online.
+If the machine goes online, this mail is sent.
+Mail to local machines is sent immediately.
 
+While the other \MTA{}s are more general purpose \MTA{}s, \masqmail\ aims on special situations only.
+Nevertheless can it handle ordinary mail transfers too.
 
-% briefly discuss the border between small MTAs (sendmail, masqmail) and state-of-the-art mailservers (postfix) and groupware (notes, exchange): give usecases.
+\masqmail\ is released under the \GPL, which makes it \freesw. The latest stable version is 0.2.21 from November 2005.
+
+The program's new homepage \citeweb{masqmail:homepage} provides further information about this \MTA.