# HG changeset patch # User meillo@marmaro.de # Date 1228835042 -3600 # Node ID 27ddf25061572bcc979ed95670136e0d25f01a4c # Parent aa1fb227e68e52fafd2d45aedbacb7949a9b83c3 outsourced floats; minor stuff diff -r aa1fb227e68e -r 27ddf2506157 thesis/input/comm-classification.tex --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/thesis/input/comm-classification.tex Tue Dec 09 16:04:02 2008 +0100 @@ -0,0 +1,30 @@ +\karnaughmap{2}{}{ + {\parbox{\kvunitlength}{asynchronous\\(messages)}} + {written} + {\parbox{\kvunitlength}{synchronous\\(dialog)}} + {recorded} +}{ + {\parbox{0.8\kvunitlength}{email\\\NAME{SMS}}} + {\parbox{0.8\kvunitlength}{voice mail\\video messages}} + {\parbox{0.8\kvunitlength}{\NAME{IM}\\chat}} + {\parbox{0.8\kvunitlength}{VoIP\\video conferencing}} +}{} + + + +%\begin{verbatim} +% --------------------------------------------------- +% | | | +% messages | email | voicemail | +% asynchron | SMS | video messages | +% | | | +% --------------------------------------------------- +% | | | +% dialog | IM | VoIP | +% synchron | chat | video conference | +% | | | +% --------------------------------------------------- +% | | | +% | written | recorded | +% | | | +%\end{verbatim} diff -r aa1fb227e68e -r 27ddf2506157 thesis/input/comm-lifecycle.tex --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/thesis/input/comm-lifecycle.tex Tue Dec 09 16:04:02 2008 +0100 @@ -0,0 +1,20 @@ +\begin{verbatim} +| | | | ******* | | +| | | |*#** **| telefax | +| | | ***** email ***#** | +| | | ** | | *****| +| | |*#** | | | +| | *** IM | | | +| | ** | | | | +| | *#* | | | | +| | ** VoIP | | | | +| | ** | | | | +| voice * | | | | +| video mail** | | | | +| mess. #**| | | | | +| #**** | | | | | +|**** | | | | | +---------------------------------------------------------------- +| | | | | | +| introduct. | growth | mature | saturation | decline | +\end{verbatim} diff -r aa1fb227e68e -r 27ddf2506157 thesis/input/email-swot.tex --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/thesis/input/email-swot.tex Tue Dec 09 16:04:02 2008 +0100 @@ -0,0 +1,17 @@ +\begin{verbatim} + ---------------------------------------------------- + | | | + strength | standard | | + of email | modular,extensible| | + | | | + ---------------------------------------------------- + | big data transfer | | + weaknesses | too big for phone | | + of email | | spam | + | | | + ---------------------------------------------------- + | | | + | opportunities of | threats of | + | market | market | + | | | +\end{verbatim} diff -r aa1fb227e68e -r 27ddf2506157 thesis/input/mta-comparison.tex --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/thesis/input/mta-comparison.tex Tue Dec 09 16:04:02 2008 +0100 @@ -0,0 +1,15 @@ +\begin{tabular}[hbt]{| p{0.13\textwidth} || p{0.13\textwidth} | p{0.13\textwidth} | p{0.13\textwidth} | p{0.13\textwidth} | p{0.13\textwidth} |} + \hline + & sendmail & exim & qmail & postfix & masqmail \\ + \hline + version regarded & & & & & \\ + \hline \hline + First release & 1983 & 1995 & 1996 & 1999 & 1999 \\ + \hline + Lines of code (with sloccount on debian packages)& 93k & 54k & 18k & 92k & 14k \\ + \hline + Architecture & monolithic & monolithic & modular & modular & monolithic \\ + \hline + Design goals & flexibility & general, flexible \& extensive facilities for checking & security & performance and security & for non-permanent Internet connection \\ + \hline +\end{tabular} diff -r aa1fb227e68e -r 27ddf2506157 thesis/tex/2-MarketAnalysis.tex --- a/thesis/tex/2-MarketAnalysis.tex Sun Dec 07 17:29:29 2008 +0100 +++ b/thesis/tex/2-MarketAnalysis.tex Tue Dec 09 16:04:02 2008 +0100 @@ -32,47 +32,13 @@ -%\begin{figure} -% \begin{center} -%\begin{verbatim} -% --------------------------------------------------- -% | | | -% messages | email | voicemail | -% asynchron | SMS | video messages | -% | | | -% --------------------------------------------------- -% | | | -% dialog | IM | VoIP | -% synchron | chat | video conference | -% | | | -% --------------------------------------------------- -% | | | -% | written | recorded | -% | | | -%\end{verbatim} -% \end{center} -% \caption{Classification of electronic communication} -% \label{fig:comm-classification} -%\end{figure} - - \input{kvmacros} \kvunitlength=3cm \kvnoindex -\begin{figure} +\begin{figure} %fixme: table or figure? \begin{center} -\karnaughmap{2}{}{ - {\parbox{\kvunitlength}{asynchronous\\(messages)}} - {written} - {\parbox{\kvunitlength}{synchronous\\(dialog)}} - {recorded} -}{ - {\parbox{0.8\kvunitlength}{email\\\NAME{SMS}}} - {\parbox{0.8\kvunitlength}{voice mail\\video messages}} - {\parbox{0.8\kvunitlength}{\NAME{IM}\\chat}} - {\parbox{0.8\kvunitlength}{VoIP\\video conferencing}} -}{} + \input{input/comm-classification.tex} \end{center} \caption{Classification of electronic communication} \label{fig:comm-classification} @@ -90,26 +56,7 @@ \begin{figure} \begin{center} - \begin{verbatim} -| | | | ******* | | -| | | |*#** **| telefax | -| | | ***** email ***#** | -| | | ** | | *****| -| | |*#** | | | -| | *** IM | | | -| | ** | | | | -| | *#* | | | | -| | ** VoIP | | | | -| | ** | | | | -| voice * | | | | -| video mail** | | | | -| mess. #**| | | | | -| #**** | | | | | -|**** | | | | | ----------------------------------------------------------------- -| | | | | | -| introduct. | growth | mature | saturation | decline | - \end{verbatim} + \input{input/comm-lifecycle.tex} \end{center} \caption{Life cycle of electronic communication technologies} \label{fig:comm-lifecycle} @@ -183,6 +130,11 @@ The market's main threat is \emph{spam}, also named \name{junk mail} or \name{unsolicited commercial email} (\NAME{UCE}). Panda Security and Commtouch state in their \name{Email Threats Trend Report} for the second Quarter of 2008: ``Spam levels throughout the second quarter averaged 77\%, ranging from a low of 64\% to a peak of 94\% of all email [...]''\cite[page 4]{panda:email-threats}. The report sees the main reason in the bot nets consisting of zombie computers: ``Spam and malware levels remain high for yet another quarter, powered by the brawny yet agile networks of zombie \NAME{IP}s.''\cite[page 1]{panda:email-threats} This is supported by IronPort Systems: ``More than 80 percent of spam now comes from a `zombie'---an infected \NAME{PC}, typically in a consumer broadband network, that has been hijacked by spammers.''\cite{ironport:zombie-computers}. Positive for \MTA{}s is, that they are not the main source for spam, but it is only a small delight. Spam is a general weakness of the email system, because it can not prevent it. +\begin{quote} +Since receivers pay the bulk of the costs for spam (including most obviously their time to delete all that incoming spam), spam use will continue to rise until effective technical and legal countermeasures are deployed, or until people can no longer use email. +\url{http://www.dwheeler.com/guarded-email/guarded-email.html} +\end{quote} + Opportunities of the market are large data transfers, coming from multimedia content, which becomes popular. If email is used as basis for unified messaging, lots of voice and video mail will need to be transferred. Email is weak related to that kind of data: the data needs to be encoded to \NAME{ASCII} and and stresses mail servers a lot. The use of various hardware to access mail is another opportunity of the market. The software and infrastructure needed to transfer mail within this network might be a weakness of the email system. %fixme: think about that @@ -196,23 +148,7 @@ \begin{figure} \begin{center} - \begin{verbatim} - --------------------------------------------------- - | | | - strength | standard | | - of email | modular,extensible| | - | | | - --------------------------------------------------- - | big data transfer| | - weaknesses | too big for phone| | - of email | | spam | - | | | - --------------------------------------------------- - | | | - | opportunities of | threats of | - | market | market | - | | | - \end{verbatim} + \input{input/email-swot.tex} \end{center} \caption{\NAME{SWOT} analysis for email} \label{fig:email-swot} @@ -253,7 +189,8 @@ %FIXME: add reference to push email -\subsubsection*{Internet Mail 2000} +\subsubsection*{New email protocols} + Another concept to redesign the electronic mail system, but this time focused on mail transfer is named ``Internet Mail 2000''. It was proposed by Daniel J.\ Bernstein, the creator of \name{qmail}. Similar approaches were independently introduced by others too. As main change it makes the sender have the responsibility of mail storage; only a notification about a mail message gets send to the receiver, who can fetch the message then from the sender's server. This is in contrast to the \NAME{SMTP} mail architecture, where mail and the responsibility for it is transferred from the sender to the receiver. @@ -262,6 +199,9 @@ %FIXME: add references for IM2000 +%add ``guarded email'' by dwheeler + +%maybe add a third one @@ -276,6 +216,7 @@ \section{What will be important} +\label{sec:what-will-be-important} Now that it is explained why email will survive (in some changed but related form), it is time to think about the properties required for \mta{}s in the next years. Because as the fields and kinds of usage change, the requirement change too. Provider independence through running an own mail server at home asks for easy configuration of the \MTA. Providers have specialists to configure the systems, but ordinary people do not. Solutions are either having some home service system for computer configuration established with specialists coming to ones home to set up the systems; like it is already common for problems with the power and water supply systems. Or configuration needs to be easy and fool-prove, to be done by the owner himself. The latter solution depends on standardized parts that fit together seamlessly. The technology must not be a problem itself. Only settings custom to the users environment should be left open for him to set. This of course needs to be doable using a simple configuration interface like a web interface. Non-technical educated users should be able to configure the system. diff -r aa1fb227e68e -r 27ddf2506157 thesis/tex/3-MailTransferAgents.tex --- a/thesis/tex/3-MailTransferAgents.tex Sun Dec 07 17:29:29 2008 +0100 +++ b/thesis/tex/3-MailTransferAgents.tex Tue Dec 09 16:04:02 2008 +0100 @@ -68,14 +68,13 @@ \section{Popular MTAs} %todo: include market share analyses here +<< some info about market shares >> One would not use a program for a job it is not suited for. Therefor only \mta{}s that are mostly similar to \masqmail\ are regarded here. These are \emph{sendmail-compatible} ``smart'' \freesw\ \MTA{}s that focus on mail transfer. For the comparison, five programs are taken: \sendmail, \name{exim}, \name{qmail}, \name{postfix}, and \masqmail. The four alternatives to \masqmail\ are the most important representatives of the regarded group. % FIXME: add ref that affirm that -\name{courier-mta} is also a member of this group, being even closer to \name{groupware} than \name{postfix}. It is excluded here, because the \NAME{IMAP} and webmail parts of the mail server suite are more in focus than its \MTA. Common mail server setups even bundle \name{courier-imap} with \name{postfix}. %fixme: need this sentence? - -Other members are: \name{smail}, \name{zmailer}, \name{mmdf}, and more; they all are less important and rarely used. +Other members are: \name{smail}, \name{zmailer}, \name{mmdf}, and \name{courier-mta}; they all are less important and rarely used. Following is a small introduction to each of the five programs chosen for comparison, except \masqmail\ which already was introduced in chapter \ref{chap:introduction}. @@ -140,51 +139,44 @@ \section{Comparison of MTAs} -<< general fact in table \ref{tab:mta-comparison} >> +This section tries not to provide an overall \MTA\ comparison, because this is already done by others: Including -Refer to \cite{hafiz05}. +\url{http://shearer.org/MTA_Comparison} +\url{http://www.geocities.com/mailsoftware42/} +\url{http://fanf.livejournal.com/50917.html} +\url{http://archives.neohapsis.com/archives/postfix/2006-07/1762.html} + + +For a discussion on \mta\ architectures (comparing \sendmail, \name{qmail}, \name{postfix}, and \name{sendmail X}) it is refered to Hafiz \cite{hafiz05}. + +Here provided is an overview on a selection of important properties, covering the four previously introduced programs. Table \ref{tab:mta-comparison} provides it. + \begin{table} -\begin{tabular}[hbt]{| p{0.13\textwidth} || p{0.13\textwidth} | p{0.13\textwidth} | p{0.13\textwidth} | p{0.13\textwidth} | p{0.13\textwidth} |} -\hline - - & sendmail & exim & qmail & postfix & masqmail \\ -\hline \hline -First release & 1983 & 1995 & 1996 & 1999 & 1999 \\ -\hline -Lines of code (with sloccount on debian packages)& 93k & 54k & 18k & 92k & 14k \\ -\hline -Architecture & monolithic & monolithic & modular & modular & monolithic \\ -\hline -Design goals & flexibility & general, flexible \& extensive facilities for checking & security & performance and security & for non-permanent Internet connection \\ -\hline -Market share (by Bernstein in 2001) & 42\% & 1.6\% & 17\% & 1.6\% & (unknown) \\ -\hline - -\end{tabular} -\caption{Comparison of MTAs} -\label{tab:mta-comparison} + \begin{center} + \input{input/mta-comparison.tex} + \end{center} + \caption{Comparison of MTAs} + \label{tab:mta-comparison} \end{table} \subsection{about market share} +\url{http://www.oreillynet.com/lpt/a/6849} + +\url{http://www.mailradar.com/mailstat/} + +Market share (by Bernstein in 2001): sendmail 42\% , exim 1.6\% , qmail 17\% , postfix 1.6\%. +masqmail has no relevant market share (debian popcon) + + + \subsection{About architecture} \subsection{Security comparison} -\url{http://shearer.org/MTA_Comparison} - -\url{http://www.geocities.com/mailsoftware42/} - -\url{http://fanf.livejournal.com/50917.html} - -\url{http://archives.neohapsis.com/archives/postfix/2006-07/1762.html} - -\url{http://www.oreillynet.com/lpt/a/6849} - -\url{http://www.mailradar.com/mailstat/} @@ -209,7 +201,7 @@ << used it myself >> -<< had problems with it >> +<< had problems with it >> @@ -226,7 +218,18 @@ -<< from the practice of programming: are the names good? check the significant number of characters. (intern: 31char, extern: 6char caseless; ProgC p.184) >> + + +Ref back to \ref{sec:what-will-be-important}: + +provider indepencence -> easy config: +\sendmail\ and \name{qmail} appear to have bad positions at this point. Their configuration is complex, thus they would need simplification wrappers around them to provide easy configuration. + +performance not so important: +\name{postfix} focuses much on performance, this might not be an important point then. + +security: +It seems as if all widely used \mta{}s provide good security nowadays. \name{qmail}'s architecture, also used in \name{postfix}, is generally seen to be conceptually more secure, however. ---