122 lines
4.7 KiB
TeX
122 lines
4.7 KiB
TeX
\section{Using POP3}\label{sec:pop3}
|
|
%
|
|
\begin{description}
|
|
\item[Used files:] pop3.scm pop3-obsolete.scm
|
|
\item[Name of the package:] pop3 pop3-obsolete.scm
|
|
\end{description}
|
|
%
|
|
\subsection{Overview}
|
|
|
|
The POP3 protocol allows access to email on a maildrop server. It is
|
|
often used in configurations where users connect from a client machine
|
|
which doesn't have a permanent network connection or isn't always
|
|
turned on, situations which make local SMTP delivery impossible. It is
|
|
the most common form of email access provided by Internet Service
|
|
Providers.
|
|
|
|
Two types of authentication are commonly used. The first, most basic
|
|
type involves sending a user's password in clear over the network, and
|
|
should be avoided. Unfortunately many POP3 clients only implement this
|
|
basic authentication. The digest authentication system involves the
|
|
server sending the client a ``challenge'' token; the client encodes
|
|
this token with the pass phrase and sends the coded information to the
|
|
server. This method avoids sending sensitive information over the
|
|
network.
|
|
|
|
Once connected, a client may request information about the number and
|
|
size of the messages waiting on the server, download selected messages
|
|
(either their headers or the entire content), and delete selected
|
|
messages.
|
|
|
|
|
|
\subsection{Entry points}
|
|
|
|
\begin{defundesc}{pop3-connect}{\ovar{host \ovar{logfile}}}{connection}
|
|
Connect to the maildrop server named \semvar{host}. Optionally log
|
|
the conversation with the server to \semvar{logfile}, which will be
|
|
appended to if it exists, and created otherwise. The environment
|
|
variable \ex{MAILHOST}, if set, will override the value of
|
|
\semvar{host}.
|
|
\end{defundesc}
|
|
|
|
In the further descriptions of the procedures, \semvar{connection}
|
|
always refers to the result of \ex{pop3-\ob{}connect}.
|
|
|
|
\begin{defundesc}{pop3-login} {connection \ovar{login \ovar{password}}}{status}
|
|
Log in to the mailhost. If a \semvar{login} and \semvar{password}
|
|
are not provided, they are first searched for in the user's ~/.netrc
|
|
file. USER/PASS authentication will be tried first, and if
|
|
this fails, APOP authentication (secure) will be tried.
|
|
\end{defundesc}
|
|
|
|
\begin{defundesc}{pop3-login/APOP} {connection login password}{status}
|
|
Log in to the mailhost using APOP authentication\footnote{The encryption
|
|
(MD5) is currently done by an extern program that your system must
|
|
provide. The expected name of the program is \ex{md5sum}. If your system
|
|
uses another program for computing a MD5 message digest, change the
|
|
program's name in \ex{md5-digest}.}.
|
|
\end{defundesc}
|
|
|
|
\begin{defundesc}{pop3-stat}{connection}{number bytes}
|
|
Return the number of messages and the number of bytes waiting in the
|
|
maildrop.
|
|
\end{defundesc}
|
|
|
|
\begin{defundesc}{pop3-get}{connection msgid}{status}
|
|
Download message number \semvar{msgid} from the mailhost.
|
|
\semvar{msgid} must be positive and less than the number of messages
|
|
returned by the \ex{pop3-\ob{}stat} call. The message contents are sent to
|
|
\ex{(cur\ob{}rent-\ob{}out\ob{}put-\ob{}port)}.
|
|
\end{defundesc}
|
|
|
|
\begin{defundesc}{pop3-headers}{connection msgid}{status}
|
|
Download the headers of message number \semvar{msgid}. The data is sent to
|
|
\ex{(cur\ob{}rent-\ob{}out\ob{}put-\ob{}port)}.
|
|
\end{defundesc}
|
|
|
|
\begin{defundesc}{pop3-last}{connection}{msgid}
|
|
Return the highest accessed message-id number for the current
|
|
session. This isn't in the RFC, but seems to be supported by several
|
|
servers.
|
|
\end{defundesc}
|
|
|
|
\begin{defundesc}{pop3-delete}{connection msgid}{status}
|
|
Mark message number \semvar{msgid} for deletion. The message will
|
|
not be deleted until the client logs out.
|
|
\end{defundesc}
|
|
|
|
\begin{defundesc}{pop3-reset}{connection}{status}
|
|
Any messages which have been marked for deletion are unmarked.
|
|
\end{defundesc}
|
|
|
|
\begin{defundesc}{pop3-quit}{connection}{status}
|
|
Close the connection with the mailhost.
|
|
\end{defundesc}
|
|
|
|
\subsubsection*{Obsolete procedures}
|
|
|
|
Names in further versions of \ex{pop3} contained a colon (`\ex{:}')
|
|
after the prefix `\ex{pop3-}'. This is now changed to a hyphen
|
|
('\ex{-}'), accordingly to SUnet's philosophy. If you need the old
|
|
names, use the \ex{pop3\=obsolete}-package that maps the old names to
|
|
the new ones.
|
|
|
|
\subsection{Related work}
|
|
|
|
\begin{itemize}
|
|
\item Emacs is distributed with a C program called \ex{movemail} which
|
|
can be compiled with support for the POP protocol. There is also an
|
|
Emacs Lisp library called \ex{pop3.el} by Richard Pieri which
|
|
includes APOP support.
|
|
\item Shriram Krishnamurth has written a POP3 library for MzScheme (as
|
|
well as support for the NNTP protocol, for SMTP, \ldots).
|
|
\item Siod (a small-footprint Scheme implementation by George Carette)
|
|
includes support for the POP3 protocol.
|
|
\item rfc1939 describes the POP3 protocol.
|
|
\end{itemize}
|
|
|
|
%%% Local Variables:
|
|
%%% mode: latex
|
|
%%% TeX-master: t
|
|
%%% End:
|