\input{gl2.slide-header-beamer}%
\errorcontextlines=99
%% Subtopic Number = '1.113.1'
%% Title from filename: 'Configure and manage inetd, xinetd, and related services'
%% Weight: 4
%% Description:
%% Candidates should be able to configure which services are
%%        available through inetd, use tcpwrappers to allow or deny services on a
%%        host-by-host basis, manually start, stop, and restart internet services,
%%        configure basic network services including telnet and ftp. Set a service
%%        to run as another user instead of the default in inetd.conf.
%% Key files, terms, and utilities include:
%%        /etc/inetd.conf
%%        /etc/hosts.allow
%%        /etc/hosts.deny
%%        /etc/services
%%        /etc/xinetd.conf
%%        /etc/xinetd.log
\title{1.113.1\\Configure and manage inetd, xinetd, and related
  services\\Weight 4}%
\author[Angus Lees]{Angus Lees \texttt{gus@inodes.org} \and Geoffrey Robertson \texttt{ge@ffrey.com} \and Nick Urbanik \texttt{nicku@nicku.org}\\
  {\tiny This document Licensed under GPL---see
    section~\ref{sec:license}}}%
\subtitle{Linux Professional Institute Certification --- 102}%
\mode<article>{\chead{1.113.1}}%


\begin{document}
\maketitle
\mode<article>{\thispagestyle{empty}}

\begin{frame}
  \frametitle{Outline}
  \mode<presentation>
  {%
    %\footnotesize
    \begin{multicols}{2}
      \tableofcontents
    \end{multicols}
    % You might wish to add the option [pausesections]
  }%
  \mode<article>
  {%
    \tableofcontents
  }%
\end{frame}

\section{Context}
\label{sec:context}

\begin{frame}
  \frametitle{Topic 113 Networking Services [24]}%
  \framesubtitle{Where we are up to}%
    \begin{description}
    % \uline depends on \usepackage[normalem]{ulem}:
    \item[1.113.1] \textbf{\uline{Configure and manage inetd, xinetd,
          and related services [4]}}
    \item[1.113.2] Operate and perform basic configuration of sendmail [4]
    \item[1.113.3] Operate and perform basic configuration of Apache [4]
    \item[1.113.4] Properly manage the NFS, smb, and nmb daemons  [4]
    \item[1.113.5] Setup and configure basic DNS services [4]
    \item[1.113.7] Set up secure shell (OpenSSH) [4]
    \end{description}
\end{frame}

\section{Objective}
\label{sec:objective}


\begin{frame}
  \frametitle{Description of Objective}%
  \framesubtitle{1.113.1\ \ Configure and manage \texttt{inetd},
    \texttt{xinetd}, and related services}%
  \mode<presentation>{\Large}%
  Candidates should be able to configure which services are
  available through \texttt{inetd}, use tcpwrappers to allow or deny
  services on a host-by-host basis, manually start, stop, and restart
  internet services, configure basic network services including
  \texttt{telnet} and \texttt{ftp}. Set a service to run as another
  user instead of the default in \texttt{inetd.conf}.
\end{frame}

\begin{frame}
  \frametitle{Key files, terms, and utilities include:}%
  \framesubtitle{1.113.1\ \ Configure and manage \texttt{inetd},
    \texttt{xinetd}, and related services}%
  \mode<presentation>{\large}%
  \begin{description}
  \item[\texttt{/etc/inetd.conf}] --- configuration file for the older
    \texttt{inetd}
  \item[\texttt{/etc/hosts.allow}] --- TCP Wrappers configuration
    file, consulted first
  \item[\texttt{/etc/hosts.deny}] --- TCP Wrappers configuration file,
    consulted second
  \item[\texttt{/etc/services}] --- file mapping service names
    $\leftrightarrow$ network ports
  \item[\texttt{/etc/xinetd.conf}] --- configuration file for
    \texttt{xinetd}, which has built-in support for TCP Wrappers, so
    is now used more than \texttt{inetd}
  \item[\texttt{/etc/xinetd.log}] --- a file that appears to exist
    only in LPI objectives, but see
    \par%
    \cmdbox{man 5 xinetd.log}
  \end{description}
\end{frame}


% \begin{frame}[fragile]

% \frametitle{Configure and manage inetd, xinetd, and related
% services}
% \framesubtitle{Objective}

% Candidates should be able to configure which services are available
% through inetd, use tcpwrappers to allow or deny services on a
% host-by-host basis, manually start, stop, and restart internet
% services, configure basic network services including \textbf{telnet} and
% \textbf{ftp}. Set a service to run as another user instead of the
% default in \texttt{inetd.conf}.

% \end{frame}


% \begin{frame}[fragile]

% \frametitle{Configure and manage inetd, xinetd, and related
% services}
% \framesubtitle{Key files, terms and utilities}
% \begin{semiverbatim}
% /etc/inetd.conf
% /etc/hosts.allow
% /etc/hosts.deny
% /etc/services
% /etc/xinetd.conf
% /etc/xinetd.log
% \end{semiverbatim}
% \end{frame}


\section{inetd, xinetd}
\label{sec:inetd-xinetd}


\begin{frame}
  \frametitle{\texttt{inetd}/\texttt{xinetd}}
  \begin{itemize}
  \item The internet ``super-server''
  \item A daemon which listens on many ports and fires off the
    appropriate command to handle incoming requests
  \item \texttt{inetd} is used in older/smaller systems
    \begin{itemize}
    \item Controlled through \texttt{/etc/inetd.conf}
    \end{itemize}
  \item \textbf{xinetd} is an enhanced replacement
    \begin{itemize}
    \item Controlled through \texttt{/etc/xinetd.conf}\ldots
    \item \ldots\,and through individual files in directory
      \texttt{/etc/xinetd.d/}
    \end{itemize}
  \end{itemize}
\end{frame}

\subsection{\texttt{inetd.conf}}
\label{sec:inetd.conf}

\begin{frame}[fragile]
  \framesubtitle{inetd.conf}
  Fields are:\par\noindent%
  \textit{service\_name} \textit{sock\_type} \textit{proto} \textit{flags}
  \textit{user} \textit{server\_path} \textit{args}
  \scriptsize
\begin{semiverbatim}
# UW-IMAP server
imap2  stream  tcp  nowait  root  /usr/sbin/tcpd  /usr/sbin/imapd
imap3  stream  tcp  nowait  root  /usr/sbin/tcpd  /usr/sbin/imapd
imaps  stream  tcp  nowait  root  /usr/sbin/tcpd  /usr/sbin/imapd

# Exim mail server
smtp   stream  tcp  nowait  mail  /usr/sbin/exim  exim -bs
\end{semiverbatim}
\end{frame}


\begin{frame}[fragile]
  \framesubtitle{inetd.conf -- Internal services}%
  Built-in services (often disabled)
  \par%
\begin{semiverbatim}
echo     stream  tcp  nowait  root  internal
echo     dgram   udp  wait    root  internal
chargen  stream  tcp  nowait  root  internal
chargen  dgram   udp  wait    root  internal
discard  stream  tcp  nowait  root  internal
discard  dgram   udp  wait    root  internal
daytime  stream  tcp  nowait  root  internal
daytime  dgram   udp  wait    root  internal
time     stream  tcp  nowait  root  internal
time     dgram   udp  wait    root  internal
\end{semiverbatim}
\end{frame}

\section{tcpwrappers}
\label{sec:tcpwrappers}

\begin{frame}[fragile]
  \frametitle{hosts.allow / hosts.deny}%
  \framesubtitle{``TCP Wrappers'' aka \textbf{tcpd}}%
  Manpage is \texttt{hosts\_access}(5)
\begin{semiverbatim}
# /etc/hosts.allow
sshd:  ALL
imapd: 10.0.6.19
ALL:   10.0.128.96/255.255.255.224
\end{semiverbatim}
\par
\begin{semiverbatim}
# /etc/hosts.deny
#ALL:  PARANOID
ALL:   ALL
\end{semiverbatim}
\end{frame}


\section{xinetd}
\label{sec:xinetd}


\begin{frame}[fragile]
  \frametitle{xinetd}
  \begin{itemize}
  \item Same function as \texttt{inetd}
  \item Has built-in support for TCP Wrappers, so is now used for
    recent distributions instead of \texttt{inetd}
  \item package management system (i.e., \texttt{dpkg}, \texttt{rpm})
    drops a file into directory \sloppypar\texttt{/etc/xinetd.d/} instead of
    having to edit \texttt{/etc/inetd.conf}
  \item Here is such a file for the \texttt{exim} mail server to run
    under \texttt{xinetd}:
\begin{semiverbatim}
service smtp
\{
        socket_type     = stream
        protocol        = tcp
        wait            = no
        user            = mail
        server          = /usr/sbin/exim
        server_args     = -bs
\}
\end{semiverbatim}
  \end{itemize}
\end{frame}

\mode<presentation>
{%
\begin{frame}
  \frametitle{Topics Covered}
  %\footnotesize
  %\begin{multicols}{2}
    \tableofcontents[pausesections,pausesubsections]
  %\end{multicols}
  % You might wish to add the option [pausesections]
\end{frame}
}


\section{License Of This Document}
\label{sec:license}

\begin{frame}
  \frametitle{License Of This Document}%
  \raggedright%
  Copyright \copyright\ 2005, 2003 Angus Lees <gus@inodes.org>,
  Geoffrey Robertson <ge@ffrey.com> and Nick Urbanik
  <nicku@nicku.org>.
  \par
  Permission is granted to make and distribute
  verbatim copies or modified versions of this document provided that
  this copyright notice and this permission notice are preserved on
  all copies under the terms of the GNU General Public License as
  published by the Free Software Foundation---either version 2 of the
  License or (at your option) any later version.
\end{frame}
\end{document}