98 lines
3.8 KiB
HTML
98 lines
3.8 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
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<!--Converted with LaTeX2HTML 96.1-c (Feb 29, 1996) by Nikos Drakos (nikos@cbl.leeds.ac.uk), CBLU, University of Leeds -->
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<HTML>
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<HEAD>
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<TITLE>Running in Server Mode</TITLE>
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</HEAD>
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<BODY LANG="EN">
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<A HREF="node1.html"><IMG WIDTH=65 HEIGHT=24 ALIGN=BOTTOM ALT="contents" SRC="contents_motif.gif"></A> <BR>
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<B> Next:</B> <A HREF="node107.html">The Point-to-Point Protocol</A>
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<B>Up:</B> <A HREF="node92.html">Serial Line IP</A>
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<B> Previous:</B> <A HREF="node105.html">mode and default</A>
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<BR> <P>
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<H1><A NAME="SECTION009400000">Running in Server Mode</A></H1>
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<A NAME="slipserver"></A>
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<A NAME="4017"></A>
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<A NAME="3960"></A>
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Setting up your SLIP client was the hard part. Doing the opposite,
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namely configuring your host to act as a SLIP server, is much easier.
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<P>
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One way to do this is to to use dip in server mode, which can
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be achieved by invoking it as diplogin. Its main configuration
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file is /etc/diphosts, which associates login names with the
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address this host is assigned. Alternatively, you can also use
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sliplogin, a BSD-derived tool that features a more flexible
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configuration scheme that lets you execute shell scripts whenever a
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host connects and disconnects. It is currently at Beta.
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<P>
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<A NAME="3965"></A>
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Both programs require that you set up one login account per SLIP
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client. For instance, assume you provide SLIP service to Arthur Dent
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at dent.beta.com, you might create an account named dent
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by adding the following line to your passwd file:
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<P>
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<pre>
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dent:*:501:60:Arthur Dent's SLIP account:/tmp:/usr/sbin/diplogin
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</pre>
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<P>
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Afterwards, you would set dent's password using the
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passwd utility.
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<P>
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<A NAME="4018"></A>
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Now, when dent logs in, dip will start up as a server.
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To find out if he is indeed permitted to use SLIP, it will look
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up the user name in /etc/diphosts. This file details the access
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rights and connection parameter for each SLIP user. A sample entry for
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dent could look like this:
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<P>
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<PRE>
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</PRE>
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dent::dent.beta.com:Arthur Dent:SLIP,296
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<P>
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<A NAME="3980"></A>
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The first of the colon-separated fields is the name the user
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must log in as. The second field may contain an additional
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password (see below). The third is the hostname or IP-address
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of the calling host. Next comes an informational field without
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any special meaning (yet). The last field describes the connection
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parameters. This is a comma-separated list specifying the
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protocol (currently one of SLIP or CSLIP),
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followed by the MTU.
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<P>
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When dent logs in, diplogin extracts the information on
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him from the diphosts file, and, if the second field is not
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empty, prompts for an ``external security password''. The string
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entered by the user is compared to the (unencrypted) password from
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diphosts. If they do not match, the login attempt is rejected.
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<P>
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Otherwise, diplogin proceeds by flipping the serial line to CSLIP
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or SLIP mode, and sets up the interface and route. This connection
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remains established until the user disconnects and the modem drops the
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line. diplogin will then return the line to normal line
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discipline, and exit.
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<P>
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<A NAME="3989"></A>
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<A NAME="3990"></A>
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diplogin requires super-user privilege. If you don't have
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dip running setuid root, you should make diplogin a
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separate copy of dip instead of a simple link. diplogin
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can then safely be made setuid, without affecting the status of
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dip itself.
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<P>
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<A NAME="4019"></A>
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<A NAME="3999"></A>
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<A NAME="4000"></A>
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<P>
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%
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<P>
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<HR><A HREF="node1.html"><IMG WIDTH=65 HEIGHT=24 ALIGN=BOTTOM ALT="contents" SRC="contents_motif.gif"></A> <BR>
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<B> Next:</B> <A HREF="node107.html">The Point-to-Point Protocol</A>
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<B>Up:</B> <A HREF="node92.html">Serial Line IP</A>
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<B> Previous:</B> <A HREF="node105.html">mode and default</A>
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<P><ADDRESS>
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<I>Andrew Anderson <BR>
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Thu Mar 7 23:22:06 EST 1996</I>
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</ADDRESS>
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</BODY>
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</HTML>
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