1.1 --- a/thesis/tex/3-MailTransferAgents.tex	Thu Jan 22 12:15:24 2009 +0100
     1.2 +++ b/thesis/tex/3-MailTransferAgents.tex	Thu Jan 22 12:15:47 2009 +0100
     1.3 @@ -59,9 +59,7 @@
     1.4  
     1.5  Due to \sendmail's significance in the early times of email, compatibility interfaces for \sendmail\ are important for \unix\ \MTA{}s. The reason is that many mail applications simply the \sendmail\ \MTA\ to be installed on the system. Being not \emph{sendmail-compatible} may not matter for some fields of action, but makes the program ineligible for serving as a general purpose \MTA\ on \unix\ systems. Hence being sendmail-compatible is a major property of a \mta. \MTA{}s not having a \emph{sendmail-compatible} interface or not offering it as a compatibility add-on, will not be covered here. One example for such a program is \name{Apache James}.  %FIXME: check if correct
     1.6  
     1.7 -Another separation can be done between \freesw\ \MTA{}s and proprietary ones. Many of the \MTA{}s for \unix\ systems are \freesw. Only these are regarded in the following sections, because comparing \freesw\ with proprietary or commercial software is not what typical users of programs like \masqmail\ do. %fixme: what are typical users?
     1.8 -Comparison with non-free programs may be a point for large \freesw\ projects, trying to step into the business world. Small projects, mostly used by individuals at home, %fixme: is this the right target field? see chap02
     1.9 -need to be compared against other projects of similar shape. The document is seen from \masqmail's point of view---an \MTA\ for \unix\ systems on home servers and workstations---so non-free software is out of the way.
    1.10 +Another separation can be done between \freesw\ \MTA{}s and proprietary ones. Many of the \MTA{}s for \unix\ systems are \freesw. Only these are regarded in the following sections, because comparing \freesw\ with proprietary or commercial software is not what typical users of programs like \masqmail\ do. Comparison with non-free programs may be a point for large \freesw\ projects, trying to step into the business world. Small projects, mostly used by individuals at home, need to be compared against other projects of similar shape. The document is seen from \masqmail's point of view---an \MTA\ for \unix\ systems on home servers and workstations---so non-free software is out of the way.
    1.11  
    1.12  
    1.13  
    1.14 @@ -123,9 +121,9 @@
    1.15  
    1.16  \subsubsection*{sendmail}
    1.17  \label{sec:sendmail}
    1.18 -\sendmail\ is the best known \mta, since it was one of the first and surely the one that made \MTA{}s popular. It also was shipped as default \MTA{}s by many vendors of \unix\ systems. %fixme: ref
    1.19 +\sendmail\ is the best known \mta, since it was one of the first and surely the one that made \MTA{}s popular. It also was shipped as default \MTA{}s by many vendors of \unix\ systems \citeweb{wikipedia:sendmail}.
    1.20  
    1.21 -The program was written by \person{Eric Allman} as the successor of his program \name{delivermail}. \person{Allman} was not the only one working on the program. Other people developed own versions of it and a variety of flavors came up, especially in the late eighties when Allman was inactive. %fixme: ref
    1.22 +The program was written by \person{Eric Allman} as the successor of his program \name{delivermail}. \person{Allman} was not the only one working on the program. Other people developed own versions of it and a variety of flavors came up, especially in the late eighties when Allman was inactive \cite[page~5]{vixie01}.
    1.23  
    1.24  \sendmail\ designed to transfer mails between different protocols and networks, this lead to a very flexible, though complex, configuration.
    1.25  
    1.26 @@ -142,11 +140,11 @@
    1.27  
    1.28  \subsubsection*{exim}
    1.29  \label{sec:exim}
    1.30 -\exim\ was started in 1995 by \person{Philip Hazel} at the \name{University of Cambridge}. It is a fork of \name{smail-3}, and inherited a monolithic architecture similar to \sendmail's. But having no separation of the individual components of the system did not hurt. Its security is quite good. %fixme: ref
    1.31 +\exim\ was started in 1995 by \person{Philip Hazel} at the \name{University of Cambridge}. It is a fork of \name{smail-3}, and inherited a monolithic architecture similar to \sendmail's. But having no separation of the individual components of the system did not hurt. Its security is quite good \cite{blanco05}.
    1.32  
    1.33 -\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 checkers are provided by design. %fixme: ref
    1.34 +\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 to integrate spam and malware checkers are provided by design.
    1.35  
    1.36 -The program is \freesw, released under the \GPL. The latest stable version is 4.69 from December 2007.
    1.37 +The program is \freesw, released under the \NAME{GPL}. The latest stable version is 4.69 from December 2007.
    1.38  
    1.39  One finds \exim\ on its homepage \citeweb{exim:homepage}. The standard literature is \person{Hazel}'s \exim\ book \cite{hazel01}.
    1.40  
    1.41 @@ -154,9 +152,9 @@
    1.42  
    1.43  \subsubsection*{qmail}
    1.44  \label{sec:qmail}
    1.45 -\qmail\ is seen by its community as ``a modern SMTP server which makes sendmail obsolete'' \citeweb{qmail:homepage2}. It was written by \person{Daniel~J.\ Bernstein} starting in 1995. His primary goal was to create a secure \MTA\ to replace the popular, but vulnerable, \sendmail. %fixme: ref
    1.46 +\qmail\ is seen by its community as ``a modern SMTP server which makes sendmail obsolete'' \citeweb{qmail:homepage2}. It was written by \person{Daniel~J.\ Bernstein} starting in 1995. His primary goal was to create a secure \MTA\ to replace the popular, but vulnerable, \sendmail. His own words are: ``This is why I started writing qmail: I was sick of the security holes in sendmail and other \MTA{}s.'' \cite{qmail:homepage1}.
    1.47  
    1.48 -\qmail\ first introduced many innovative concepts in \mta\ design. The most obvious contrast to \sendmail\ and \exim\ is its modular design. But \qmail\ was not the first modular \MTA. \NAME{MMDF}, which predates even \sendmail, was modular too. Regardless of \NAME{MMDF}'s modular architecture, \qmail\ is generally seen as the first security-aware \MTA. %fixme:ref
    1.49 +\qmail\ first introduced many innovative concepts in \mta\ design. The most obvious contrast to \sendmail\ and \exim\ is its modular design. But \qmail\ was not the first modular \MTA. \NAME{MMDF}, which predates even \sendmail, was modular too. Regardless of \NAME{MMDF}'s modular architecture, \qmail\ is generally seen as the first security-aware \MTA\ \citeweb{wikipedia:qmail}.
    1.50  
    1.51  The latest release of \qmail\ is version 1.03 from July 1998. In November 2007, afterwards, \qmail's source was put into the \name{public domain}. This makes it Free Software.
    1.52  
    1.53 @@ -199,8 +197,7 @@
    1.54  
    1.55  \subsubsection*{Architecture}
    1.56  
    1.57 -Architecture is most important when comparing \MTA{}s. Many other properties of a program depend on its architecture. %fixme: add ref?
    1.58 -\person{Munawar Hafiz} \cite{hafiz05} discusses in detail on \MTA\ architecture, comparing \sendmail, \qmail, \postfix, and \name{sendmail X}. \person{Jonathan de Boyne Pollard}'s \MTA\ review \cite{jdebp} is a source too.
    1.59 +Architecture is most important when comparing \MTA{}s. Many other properties of a program depend on its architecture. \person{Munawar Hafiz} \cite{hafiz05} discusses in detail on \MTA\ architecture, comparing \sendmail, \qmail, \postfix, and \name{sendmail X}. \person{Jonathan de Boyne Pollard}'s \MTA\ review \cite{jdebp} is a source too.
    1.60  
    1.61  Two different architecture types show off: monolithic and modular \mta{}s.
    1.62  
    1.63 @@ -234,9 +231,7 @@
    1.64  
    1.65  \subsubsection*{Security}
    1.66  
    1.67 -The third trend---even more security awareness---is addressed by each of the four programs. It seems as if all widely used \mta{}s provide good security nowadays. Even \sendmail\ can be considered secure today. %fixme:ref
    1.68 -But the modular architecture, used by \qmail\ and \postfix, is generally seen to be conceptually more secure, however. %fixme: ref
    1.69 -\sendmail's creators have started \name{MeTA1}, a modular \MTA\ merging the best of \qmail\ and \postfix, to replace the old \sendmail. It will be interesting to watch \exim's future---will it become modular too?
    1.70 +The third trend---even more security awareness---is addressed by each of the four programs. It seems as if all widely used \mta{}s provide good security nowadays. Even \sendmail\ can be configured to be secure today. But the modular architecture, used by \qmail\ and \postfix, is generally seen to be conceptually more secure, however. \sendmail's creators have started \name{MeTA1}, a modular \MTA\ merging the best of \qmail\ and \postfix, to replace the old \sendmail. It will be interesting to watch \exim's future---will it become modular too?
    1.71  
    1.72  
    1.73