403 lines
7.8 KiB
HTML
403 lines
7.8 KiB
HTML
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<HTML>
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<HEAD>
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<META NAME="GENERATOR" CONTENT="SGML-Tools 1.0.9">
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<TITLE>ISP-Hookup-HOWTO: How do I connect to the rest of the world?</TITLE>
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<LINK HREF="ISP-Hookup-HOWTO-3.html" REL=next>
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<LINK HREF="ISP-Hookup-HOWTO-1.html" REL=previous>
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<LINK HREF="ISP-Hookup-HOWTO.html#toc2" REL=contents>
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</HEAD>
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<BODY>
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<A HREF="ISP-Hookup-HOWTO-3.html">Next</A>
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<A HREF="ISP-Hookup-HOWTO-1.html">Previous</A>
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<A HREF="ISP-Hookup-HOWTO.html#toc2">Contents</A>
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<HR>
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<H2><A NAME="s2">2. How do I connect to the rest of the world?</A></H2>
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<P>It will be assumed that we have installed the essential
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networking software modules from your Linux distribution, and
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that you have set up which serial port that is to be used for the
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<!--
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/dev/modem
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-->
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/dev/modem.
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<P>The default configuration will usually only allow direct access
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to /dev/modem as user <CODE>root</CODE>.
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<P>To connect to ISP shell accounts directly, and to experiment with
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connection sequences, you may use the
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<!--
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minicom
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-->
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minicom program. It is pretty straight forward to
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use.
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<P>
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<H2><A NAME="ss2.1">2.1 The basic configuration</A>
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</H2>
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<P>Configuration of the machine for use on the net should be done as
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user <CODE>root</CODE>. Before proceeding any further, ensure that
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the file
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<!--
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/etc/hosts.deny
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-->
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/etc/hosts.deny contains the following line:
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<BLOCKQUOTE><CODE>
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<PRE>
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ALL: ALL
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</PRE>
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</CODE></BLOCKQUOTE>
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You would normally want to allow yourself, so add the following
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line to
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<!--
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/etc/hosts.allow
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-->
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/etc/hosts.allow:
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<BLOCKQUOTE><CODE>
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<PRE>
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ALL: LOCAL
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</PRE>
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</CODE></BLOCKQUOTE>
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Or if you insist:
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<BLOCKQUOTE><CODE>
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<PRE>
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ALL: 127.0.0.1
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</PRE>
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</CODE></BLOCKQUOTE>
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For the following, note that it is meant for those connected via
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PPP and with a dynamic IP address. If you
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have the benefit of a fixed connection, there will be some
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differences.
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<P>It is nice to have a name connected to the machine, a name that
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the dynamic IP user really can select as he or she pleases. Put
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the name in
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<!--
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/etc/HOSTNAME
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-->
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/etc/HOSTNAME:
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<BLOCKQUOTE><CODE>
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<PRE>
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roderick
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</PRE>
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</CODE></BLOCKQUOTE>
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<P>The next step is to set up the name server in
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/etc/resolv.conf
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-->
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/etc/resolv.conf:
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<BLOCKQUOTE><CODE>
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<PRE>
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search .
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nameserver 193.212.1.0
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<nidx>nameserver
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</PRE>
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</CODE></BLOCKQUOTE>
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The name server must be specified by a numeric IP
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address, and will be different from ISP to ISP. If required, you
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can have up to three different servers, each on a separate line.
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They will be requested in the sequence in which they are listed.
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<P>If you want to be able to use names like <CODE>somemachine</CODE> as
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an abbreviation for <CODE>somemachine.acme.xz</CODE>, you must
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replace the first line with:
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<BLOCKQUOTE><CODE>
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<PRE>
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search acme.xz
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</PRE>
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</CODE></BLOCKQUOTE>
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<!--
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search
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-->
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<P>A certain minimum of configuration will also be required in
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<!--
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/etc/hosts
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-->
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/etc/hosts. Most users will
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be able to manage with:
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<BLOCKQUOTE><CODE>
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<PRE>
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127.0.0.1 localhost
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0.0.0.0 roderick
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</PRE>
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</CODE></BLOCKQUOTE>
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<!--
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localhost
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-->
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Those with a fixed IP-address will
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obviously replace 0.0.0.0 with that.
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<P>Likewise, a minimum
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<!--
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/etc/networks
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-->
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/etc/networks is:
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<BLOCKQUOTE><CODE>
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<PRE>
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loopback 127.0.0.0
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localnet 0.0.0.0
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</PRE>
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</CODE></BLOCKQUOTE>
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<!--
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loopback
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-->
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<!--
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localnet
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-->
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<P>You should also set your external mail domain in
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<!--
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/etc/mailname
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-->
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/etc/mailname:
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<BLOCKQUOTE><CODE>
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<PRE>
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acme.xz
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</PRE>
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</CODE></BLOCKQUOTE>
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<P>The username and password at the ISP must be specified in
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<!--
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/etc/ppp/pap-secrets
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-->
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/etc/ppp/pap-secrets
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<BLOCKQUOTE><CODE>
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<PRE>
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dirk * PrettySecret
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</PRE>
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</CODE></BLOCKQUOTE>
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<P>For those ISPs using CHAP instead of PAP
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the filename is
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<!--
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/etc/ppp/chap-secrets
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-->
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/etc/ppp/chap-secrets.
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<P>Finally, the nitty gritty regarding the connection procedure
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itself must be specified before PPP can be initiated. This is
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done in
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/etc/ppp/chatscript
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-->
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/etc/ppp/chatscript:
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<BLOCKQUOTE><CODE>
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<PRE>
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TIMEOUT 5
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"" ATZ
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OK ATDT12345678
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ABORT "NO CARRIER"
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ABORT BUSY
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ABORT "NO DIALTONE"
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ABORT WAITING
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TIMEOUT 45
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CONNECT ""
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TIMEOUT 5
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"name:" ppp
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</PRE>
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</CODE></BLOCKQUOTE>
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<!--
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OK
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-->
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<!--
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ATDT
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-->
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<!--
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ATZ
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-->
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<!--
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TIMEOUT
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-->
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<!--
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ABORT
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-->
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<!--
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CONNECT
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-->
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Details here may have to be tuned somewhat. The phone number in
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the third line must of course be set as required. Some users may
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need to replace the <CODE>ATZ</CODE> modem initialization string with
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something more tailored for the modem being used. The last line
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specifies that one is expecting a prompt that ends with
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<CODE>name:</CODE>, and that the response should be
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<CODE>ppp</CODE> when it arrives. Other systems may have
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other login procedures.
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<P>To actually initiate a call, the PPP protocol may be
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initiated by issuing the following command:
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<BLOCKQUOTE><CODE>
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<PRE>
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exec pppd connect \
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'chat -v -f /etc/ppp/chatscript' \
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-detach crtscts modem defaultroute \
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user dirk \
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/dev/modem 38400
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</PRE>
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</CODE></BLOCKQUOTE>
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<!--
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pppd
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-->
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<!--
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chat
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-->
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<!--
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connect
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-->
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<!--
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/etc/ppp/chatscript
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-->
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<!--
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detach
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-->
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<!--
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crtscts
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-->
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<!--
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modem
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-->
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<!--
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defaultroute
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-->
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<!--
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/dev/modem
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-->
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We should now be on-air, and stay up
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until the program is killed by typing a ctrl-C.
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<!--
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ctrl-
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C
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-->
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Any messages concerning the connection will be appended
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to the system logs. To read them, try:
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<BLOCKQUOTE><CODE>
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<PRE>
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tail /var/adm/messages
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</PRE>
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</CODE></BLOCKQUOTE>
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<!--
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tail
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-->
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<!--
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/var/adm/messages
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-->
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or
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<BLOCKQUOTE><CODE>
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<PRE>
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dmesg
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</PRE>
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</CODE></BLOCKQUOTE>
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<!--
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dmesg
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-->
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<P>As long as PPP is up, you will have direct access to the
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Internet and may use programs like ftp,
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ncftp, rlogin, telnet,
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finger etc. All these programs should be part of
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the network package.
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<P>Further information concerning PPP is also available from:
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<P><CODE>
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<A HREF="file:/usr/lib/ppp/README.linux">/usr/lib/ppp/README.linux</A></CODE>
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<P><CODE>
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<A HREF="file:/usr/lib/ppp/README.linux-chat">/usr/lib/ppp/README.linux-chat</A></CODE>
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<P>Finally, an additional word about security The file
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<!--
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/etc/inetd.conf
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-->
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/etc/inetd.conf lists
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all services that your machine will offer externally. With the
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<!--
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/etc/hosts.deny
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-->
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/etc/hosts.deny file we
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have made, no external access will be allowed. For those who
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need it, access must be allowed explicitly in
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<!--
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/etc/hosts.allow
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-->
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/etc/hosts.allow.
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Local traffic may be allowed by:
|
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<BLOCKQUOTE><CODE>
|
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<PRE>
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ALL: LOCAL
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</PRE>
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</CODE></BLOCKQUOTE>
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See also <CODE>man 5 hosts_access</CODE>.
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<!--
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hosts_access
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-->
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<P>A final minor issue: A certain confusion exists regarding the
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names of the POP protocols. A definition in
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<!--
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/etc/services
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-->
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/etc/services compatible
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with just about everything is:
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<BLOCKQUOTE><CODE>
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<PRE>
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pop2 109/tcp pop-2 # PostOffice V.2
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pop3 110/tcp pop-3 pop # PostOffice V.3
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</PRE>
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</CODE></BLOCKQUOTE>
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<P><B>ALT:</B> Instead of
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<!--
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chatscript
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-->
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chatscript, one might use the much more flexible
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<!--
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dip
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-->
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dip. But not in connection with
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<!--
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diald
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-->
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diald.
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<P><B>ALT:</B> Those fortunate enough to have a permanent
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TCP/IP connection via e.g. an Ethernet may
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safely ignore anything about PPP and rather start
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concentrating about setting up their network card.
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<P><B>ALT:</B> Others may not have the possibility of using PPP,
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but may be able to use SLIP instead, for which there
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is support in much the same manner as for PPP. Another
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possibility is UUCP Others again may have to rely on
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exchange of news and email be means of SOUP A
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description for the latter case may be found in:
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<P><CODE>
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<A HREF="ftp://ftp.sol.no/user/bjorn/Linux-offline.tgz">ftp://ftp.sol.no/user/bjorn/Linux-offline.tgz</A></CODE>
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<P>The TERM program is also an option. Refer to the
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<I>Term-HOWTO</I>.
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<P>
|
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<HR>
|
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<A HREF="ISP-Hookup-HOWTO-3.html">Next</A>
|
|
<A HREF="ISP-Hookup-HOWTO-1.html">Previous</A>
|
|
<A HREF="ISP-Hookup-HOWTO.html#toc2">Contents</A>
|
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</BODY>
|
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</HTML>
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