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  \title{The Apache Web Server} 
  \author{}
  \date{27 October 2011,  6:33pm} 
  \setlength{\parindent}{0pt}
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  % label lists with stars
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  \begin{document} 

  \centerline{\Large \bf The Apache Web Server} \medskip
  \begin{center}
    {\huge ``}\textit{}{\huge ''}
    \textsc{}
  \end{center}
  % -----------------------------------
  % the toc should be 2 columns because of the \multitoc package 
  \tableofcontents




  The apache web server is the most widely used webserver on the
  internet. It is a large program with a myriad of configuration options
  and other tools.

\section{Getting Help}

  The apache webserver has very detailed documentation which should
  (eventually) help you out of any tight spots.

\begin{description}[labelindent=1cm, leftmargin=2cm, style=nextline]
 \item[\url{http://httpd.apache.org/docs/2.2/}]
    official documentation for apache version 2.2
\end{description}

\emph{ Install documentation for apache2 on a debian style linux }
\begin{lstlisting}
  sudo apt-get install apache2-doc
\end{lstlisting}

\emph{ Show options which can be used with apache  }
\begin{lstlisting}
  man apache2
\end{lstlisting}
\begin{lstlisting}
  man apache   ~(the same, for an older version)
\end{lstlisting}

\section{Installation}

\emph{ Install apache version 2 on a debian-style linux }
\begin{lstlisting}
  sudo apt-get install apache2
\end{lstlisting}
\begin{lstlisting}
  sudo aptitude install apache2    ~(the same)
\end{lstlisting}

\emph{ Test the installation from the webserver computer itself }
\begin{lstlisting}
  firefox 127.0.0.1
\end{lstlisting}
\begin{lstlisting}
  firefox localhost
\end{lstlisting}

\emph{ See what the status (running, stopped etc) of the webserver is }
\begin{lstlisting}
  sudo apache2ctl status
\end{lstlisting}

\subsection{Lamp Installation}

\emph{ Install Apache2 wth the MySQL database server and PHP on a 'debian' system }
\begin{lstlisting}
  sudo tasksel install lamp-server
\end{lstlisting}

\begin{description}[labelindent=1cm, leftmargin=2cm, style=nextline]
 \item[\url{http://www.ubuntugeek.com/how-to-install-apache2-webserver-with-phpcgi-and-perl-support-in-ubuntu-server.html}]
    how to install apache2 with php and cgi but not mysql
\end{description}

\section{Symbolic Links}

\emph{ Make apache serve documents referenced by unix-style symbolic links }
\begin{lstlisting}
  options followsymlinks
\end{lstlisting}

\section{Cgi Configuration}

\emph{ Execute all scripts in the folder as cgi scripts  }
\begin{lstlisting}
  ScriptAlias /cgi-bin/ /usr/local/apache2/cgi-bin/ 
\end{lstlisting}

\emph{ Allow cgi execution of '.cgi' and '.pl' in a particular folder  }
  \begin{lstlisting}
    <Directory /usr/local/apache2/htdocs/somedir>
    Options +ExecCGI
    AddHandler cgi-script .cgi .pl 
    </Directory> 
  \end{lstlisting}

\emph{ All cgi execution of all files in all user cgi-bin folders }
  \begin{lstlisting}
    <Directory /home/*/public_html/cgi-bin>
    Options ExecCGI
    SetHandler cgi-script
    </Directory> 
  \end{lstlisting}

\emph{ A perl script to show all environment variables }
  \begin{lstlisting}
    #!/usr/bin/perl
    print "Content-type: text/html\n\n";
    foreach $key (keys %ENV) {
      print "$key --> $ENV{$key}<br>";
    } 
  \end{lstlisting}

\subsection{Perl Cgi Support}

\begin{description}[labelindent=1cm, leftmargin=2cm, style=nextline]
 \item[\url{http://slashdot.org}]
    an example of a site using the apache perl module with the 
    web server and perl scripts
\end{description}

\emph{ Install the perl-cgi module for apache }
\begin{lstlisting}
  sudo aptitude install libapache2-mod-perl2
\end{lstlisting}

\emph{ Create a cgi folder }
\begin{lstlisting}
  sudo mkdir /home/www/cgi-bin
\end{lstlisting}

\emph{ Add to the virtual host configuration }
  \begin{lstlisting}
     ScriptAlias /cgi-bin/ /home/www/cgi-bin/
     <Directory /home/www/cgi-bin/>
       Options ExecCGI
       AddHandler cgi-script cgi pl
     </Directory>
  \end{lstlisting}

\emph{ Test perl cgi support }
  \begin{lstlisting}
  cd /home/www/cgi-bin
  sudo vim test.pl
  #!/usr/bin/perl -w
   print "Content-type: text/html\r\n\r\n";
   print "Hello there!\n";

  sudo chmod a+x test.pl
  lynx http://yourserverip/cgi-bin/test.pl
  \end{lstlisting}

\subsection{Php Installation}

\emph{ Install php5 to run with apache }
\begin{lstlisting}
  sudo aptitiude install php5 libapache2-mod-php5
\end{lstlisting}

\emph{ Install php4 to run with apache }
\begin{lstlisting}
  sudo aptitiude install php4 libapache2-mod-php4
\end{lstlisting}

\emph{ Load the php4 or 5 modules into apache }
\begin{lstlisting}
  sudo a2enmod php5
\end{lstlisting}
\begin{lstlisting}
  sudo a2enmod php4
\end{lstlisting}

\emph{ Test if the php installation worked swimmingly }
\begin{lstlisting}
  sudo nano /var/www/testphp.php
\end{lstlisting}
\begin{lstlisting}
  add the line '<?php phpinfo(); ?>'
\end{lstlisting}
\begin{lstlisting}
  lynx http://localhost/testphp.php
\end{lstlisting}

\section{Starting And Stopping The Server}

\emph{ Restart the apache server }
\begin{lstlisting}
  sudo apache2ctl restart
\end{lstlisting}

\section{Configuration Tools}


  \arrayrulecolor{gray}
  \begin{center}
  \begin{tabular}{ |rl| }
    \multicolumn{2}{c}{\textbf{ some configuration tools  }} \\
  \hline

  \texttt{ rapache } & Graphical configuration \\ 

    \hline
    \end{tabular}
    \end{center}
\section{Modules}

\begin{description}[labelindent=1cm, leftmargin=2cm, style=nextline]
 \item[\url{http://127.0.0.1/doc/apache2-doc/manual/en/mod/index.html}]
     the location of module documentation when apache2 documentation has
     been installed in the webserver
 \item[\url{http://www.debian-administration.org/articles/136}]
     how to enable a module
\end{description}

\emph{ Show all loaded modules }
\begin{lstlisting}
  apache2ctl -M
\end{lstlisting}
\begin{lstlisting}
  apachectl -M     ~(the same for older version of apache)
\end{lstlisting}
\begin{lstlisting}
  httpd -M         ~(for old versions of apache)
\end{lstlisting}

\emph{ Show which modules are enabled }
\begin{lstlisting}
  ls /etc/apache2/mods-enabled/
\end{lstlisting}

\emph{ Load the php4 module into apache }
\begin{lstlisting}
  sudo a2enmod php4; sudo apache2ctl restart
\end{lstlisting}

\section{Htaccess Configuration}

  To check if .htaccess files are actually being considered
  put junk in them and restart the server.

\emph{ Allow .htaccess files to have effect }
\begin{lstlisting}
  AllowOverride all
\end{lstlisting}

\emph{ Prevent the directives in '.htaccess' files from having any effect }
\begin{lstlisting}
  AllowOverride None
\end{lstlisting}

\section{Global Configuration}

\emph{ Show options for apache2 (which can be used with apache2ctl as well) }
\begin{lstlisting}
  man apache2
\end{lstlisting}

\emph{ Show where the global configuration file is }
\begin{lstlisting}
  apache2ctl -V | grep SERVER_CONFIG_FILE
\end{lstlisting}

\emph{ Show verbose information about the installation }
\begin{lstlisting}
  apache2ctl -V
\end{lstlisting}

\emph{ Edit the apache2 global configuration file }
\begin{lstlisting}
  sudo nano /etc/apache2/apache2.conf
\end{lstlisting}
\begin{lstlisting}
  sudo vim /etc/apache2/apache2.conf    ~(for the intrepid)
\end{lstlisting}

\emph{ Change the default document root to '/home/www/' }
\begin{lstlisting}
  DocumentRoot /home/www/
\end{lstlisting}
\begin{lstlisting}
  and the following <Directory> tag 
\end{lstlisting}
\begin{lstlisting}
  <Directory /home/www/>
\end{lstlisting}
\begin{lstlisting}
  ...
\end{lstlisting}
\begin{lstlisting}
  </Directory>
\end{lstlisting}

\emph{ Edit the configuration file for a virtual host }
\begin{lstlisting}
  sudo vim /etc/apache2/sites-available/default
\end{lstlisting}

\section{Aliases}


\section{Redirections}

\emph{ Place redirections in the ``.htaccess'' file }
\begin{lstlisting}
  Redirect / http://www.site.com
\end{lstlisting}

\emph{ Redirect any requests to '/msadc' to microsoft }
\begin{lstlisting}
  redirect /msadc http://www.microsoft.com
\end{lstlisting}

\emph{ Redirect any request to a 'cmd.exe' file to microsoft }
\begin{lstlisting}
  RedirectMatch (.*)\cmd.exe$ http://www.microsoft.com$1
\end{lstlisting}

\subsection{Using Mod Rewrite}

\begin{description}[labelindent=1cm, leftmargin=2cm, style=nextline]
 \item[\url{http://httpd.apache.org/docs/2.2/rewrite/rewrite_guide.html}]
     solving specific problems using the rewrite module
 \item[\url{http://www.tutorio.com/tutorial/enable-mod-rewrite-on-apache}]
     how to enable the rewrite module
\end{description}

\emph{ Redirect filenames ending in ``.txt.html'' to the cgi script 'text2html.cgi' }
\begin{lstlisting}
  RewriteRule ^(.*)\.txt\.html$ /cgi-bin/text2html.cgi?$1
\end{lstlisting}

  For example a request to 
\begin{lstlisting}
  www.server.org/path/file.txt.html
\end{lstlisting}
  Is translated to
\begin{lstlisting}
  www.server.org/cgi-bin/text2html.cgi?path/file.txt.html
\end{lstlisting}

\emph{ Redirect 'www.m.org' to 'www.m.org/cgi-bin/test.cgi? }
\begin{lstlisting}
  RewriteRule ^$ /cgi-bin/test.cgi?$1
\end{lstlisting}

\emph{ Allow editing of the '.htaccess' file (probably not a great idea) }
\begin{lstlisting}
  RewriteRule ^htaccess$ /cgi-bin/edit.cgi?../htdocs/.htaccess
\end{lstlisting}

  If the user makes a request to 'www.m.org/htaccess' she will be redirected to
  'www.m.org/cgi-bin/edit.cgi?../htdocs/.htaccess. If the 'edit.cgi' script
  allows editing of files, then this is one, extremely insecure way of update
  the '.htaccess' file.


\subsection{Conditional Redirections}

\emph{ Redirect requests from 192.12.131.1 to the page 'about.html' .,, }
    SetEnvIf REMOTE\_ADDR 192.12.131.1 REDIR=``redir''
    RewriteCond \%$\{$REDIR$\}$ redir
    RewriteRule \^{}/\$ /about.html
  ,,,

\section{Denying Access}

  In some cases it is advisable to disallow any web-access to
  a file on the web-server.

\emph{ Deny access from anybody to a web-folder }
\begin{lstlisting}
  deny from all
\end{lstlisting}

\emph{ Forbidd access to all files with a '.cfg' filename extension }
  \begin{lstlisting}
   <Files ~ "\.(cfg)$">
    order allow,deny
    deny from all
   </Files>
  \end{lstlisting}

\emph{ Forbid access for anyone to the file 'config.inc.php' }
  \begin{lstlisting}
    <Files config.inc.php>
      order allow,deny
      deny from all
    </Files>
  \end{lstlisting}

\section{Allow Access By Ip Address}

  Allow connections only from the ip address 192.126.12.199 .,,

    order allow deny
    deny from all
    allow from 192.126.12.199
  ,,,

\subsection{Using Basic Authentication}

  
\begin{description}[labelindent=1cm, leftmargin=2cm, style=nextline]
 \item[\url{http://www.htpasswdgenerator.com/apache/htaccess.html}]
     a simple introduction to the htaccess file
\end{description}

\emph{ Create a password file for user 'jon' to use with basic authentication }
\begin{lstlisting}
  htpasswd -c /path/to/passwordfile jon 
\end{lstlisting}

\emph{ Place the text 'restricted zone' in the title bar of the login box }
\begin{lstlisting}
  AuthName "restricted zone"
\end{lstlisting}

\emph{ Set a password for the file 'private.txt' }
  \begin{lstlisting}
    <Files private.txt>
      AuthName "Users zone"
      AuthType Basic
      AuthUserFile /pub/home/your_login/.htpasswd
    </Files>
  \end{lstlisting}

\emph{ Require a password to access all files which end with ``x.cgi'' }
  \begin{lstlisting}
    AuthType Basic
    AuthName "Password Protected"
    AuthUserFile /home/users/www/.htpasswd
    <Files ~ "\.x\.cgi$">
        Require valid-user
    </Files>
  \end{lstlisting}

\emph{ Require a password to access all files which end with ``x.cgi'' }
  \begin{lstlisting}
    AuthType Basic
    AuthName "Password Protected"
    AuthUserFile /home/users/www/.htpasswd
    <Files ~ "\.x\.cgi$">
        Require valid-user
    </Files>
  \end{lstlisting}

\emph{ Require a password to access all files which end with 'cgi' or 'txt'  }
  \begin{lstlisting}
    AuthType Basic
    AuthName "Password Protected"
    AuthUserFile /home/users/www/.htpasswd
    <Files ~ "\.(cgi|txt)$">
        Require valid-user
    </Files>
  \end{lstlisting}

\emph{ Require a password to access an entire folder }
  \begin{lstlisting}
   AuthName "Private zone"
   AuthType Basic
   AuthUserFile /pub/home/user/.htpasswd
   require valid-user
  \end{lstlisting}

  This should be placed in a '.htaccess' file in the folder
  which you wish to protect, or else in a $<$directory$>$ tag in the
  global configuration file.

\section{Log Files}


  \arrayrulecolor{gray}
  \begin{center}
  \begin{tabular}{ |rl| }
    \multicolumn{2}{c}{\textbf{ log file tools }} \\
  \hline

  \texttt{ ip2host } & Substitute servernames for ip addresses in the log files \\ 

  \texttt{ jdresolv } & Alternative to logresolv \\ 

  \texttt{ logstalgia } & Access log visualizer \\ 

  \texttt{ visitors } & Access log analyser \\ 

  \texttt{ vlogger } & Log file rotator \\ 

    \hline
    \end{tabular}
    \end{center}
\emph{ Show the apache2 error log on a debian-style linux system }
\begin{lstlisting}
  less /var/log/apache2/error.log
\end{lstlisting}

\emph{ Look in configuration files to see where the error log file is }
\begin{lstlisting}
  grep -sri errorlog /etc/apache2
\end{lstlisting}

\section{Monitoring}


  \arrayrulecolor{gray}
  \begin{center}
  \begin{tabular}{ |rl| }
    \multicolumn{2}{c}{\textbf{ apache webserver monitoring tools }} \\
  \hline

  \texttt{ apachetop } \\ 

    \hline
    \end{tabular}
    \end{center}
\section{Load Testing}


  \texttt{ jmeter } & Load testing and metering \\ 

    \hline
    \end{tabular}
    \end{center}
\section{Other Web Servers}


  \arrayrulecolor{gray}
  \begin{center}
  \begin{tabular}{ |rl| }
    \multicolumn{2}{c}{\textbf{ some alternatives to apache }} \\
  \hline

  \texttt{ mini-httpd } & A small server with cgi \\ 

  \texttt{ lighttpd } & Small server \\ 

  \texttt{ cherokee } & Another one \\ 

  \texttt{ nanoweb } & Web server written in php (!?) \\ 

  \texttt{ nginx } & \\ 

    \hline
    \end{tabular}
    \end{center}
\section{Notes}

\emph{ Restart apache only if config works }
\begin{lstlisting}
  alias restart='apache2ctl configtest && apache2ctl restart'
\end{lstlisting}

\emph{ List apache2 virtualhosts }
\begin{lstlisting}
  /usr/sbin/apache2ctl -S 2>&1 | perl -ne 'm@.*port\s+([0-9]+)\s+\w+\s+(\S+)\s+\((.+):.*@ && do { print "$2:$1\n\t$3\n"; $root = qx{grep DocumentRoot $3}; $root =~ s/^\s+//; print "\t$root\n" };'
\end{lstlisting}

\emph{ Restart the web server gracefully }
\begin{lstlisting}
  apache2ctl graceful
\end{lstlisting}

   \end{document}