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<H3 align="left"><img src="../../gx/dennis/qbubble.gif"
height="50" width="60" alt="(?) " border="0"
>pppd problem</H3>
<p><strong>From pclouds
</strong></p>
<p></strong></p>
<p align="right"><strong>Answered By Mike "Iron" Orr, Mike Ellis
</strong></p>
<P><STRONG>
Hi people
</STRONG></P>
<P><STRONG>
I try to connect to my isp using pppd:
</STRONG></P>
<pre><strong>pppd /dev/ttyS4 connect "chat -V &quot; ATZ OK ATM0 OK ATDT1260 CONNECT" modem
defaultroute crtscts -detach
</strong></pre>
<P><STRONG>
It saids:
</STRONG></P>
<pre><strong>ATZ
OK
ATM0
OK
ATDT1260
CONNECTSerial connection established.
Using interface ppp0
Connect: ppp0 &lt;--&gt; /dev/ttyS4
Serial line is looped back.
Connection terminated.
</strong></pre>
<P><STRONG>
I use modem Motorola SM56. <TT>/dev/ttyS4</TT> is a symbolic link to <TT>/dev/sm56</TT> (created
by the modem).
I can connect to that isp using rp3 with no problem.
What is "Serial line is looped back"?
Help me!
</STRONG></P>
<P><STRONG>
Thanks very much.
</STRONG></P>
<blockQuote>
<IMG SRC="../../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Iron]
It means it tried to contact the remote server, but ended up contacting
itself instead. I haven't used ppp for years, so
I don't remember the solution. Either there's a line crossed in your
serial cable (unlikely), or there's some option you add or remove in
the config fie. Check the docs for "looped back", "server" and "master".
</blockQuote>
<blockQuote>
Maybe one of the other Answer Gang members can reply better.
</blockQuote>
<blockQuote>
<IMG SRC="../../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Mike E]
Good morning!
</blockQuote>
<blockQuote>
My guess is that you're seeing the login sequence of your ISP, some of
which echo your username back to you. When the PPP daemon starts, it
sends some strange characters to your ISP, which dutifully echos them back
to you confusing pppd into thinking that it's talking to itself.
</blockQuote>
<blockQuote>
The command you quoted will get 'chat' to do the actual dialing, but as
soon as your modem has connected to the remote modem, 'chat' will exit and
the pppd will expect a PPP connection to be in place. What you need to do
is get chat to do a little more work to log you in to your ISP: I'd
suggest you try starting pppd using a modified command line, for example:
</blockQuote>
<blockquote><pre>pppd /dev/ttyS4 connect "chat -V &quot; ATZ OK ATM0 OK ATDT1260 CONNECT ogin
&lt;yourlogin&gt; assword &lt;yourpassword&gt;" modem defaultroute crtscts -detach
</pre></blockquote>
<blockQuote>
(I probably don't need to say this, but just in case, substitute your ISP
account name for &lt;yourlogin&gt; and your password for &lt;yourpassword&gt;...)
</blockQuote>
<blockQuote>
Notice that I've deliberately used "ogin" and "assword" since it's not
certain whether you will see "login" or "Login" and 'chat' is case-sensitive.
</blockQuote>
<blockQuote>
It is definitely worth checking with your ISP for their exact login
sequence: the one I've shown is a very general one and may well not work
exactly as given. I use Demon in the UK and they have an excellent on-line
helpdesk - have a look at
<A HREF="http://www.demon.net/helpdesk/general/connscp.shtml"
>http://www.demon.net/helpdesk/general/connscp.shtml</A> for an excellent
example of how their login sequence works - Demon support protocols other
than PPP, so have to query the protocol to use too. Although Demon don't
give detailed help for Linux setup, they do provide all the information
you need and several newsgroups to help users too. Hopefully your ISP will
be similarly helpful...
</blockQuote>
<blockQuote>
Incidentally, more and more ISPs are now moving away from "scripted clear
text password login" to CHAP or PAP based login sequences. These don't
send your password in cleartext, and also re-validate your credentials
periodically. However, I have no first-hand experience of these, so over
to another Gang member...
</blockQuote>
<blockQuote>
Cheers
</blockQuote>
<P><STRONG>
<IMG SRC="../../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
Thanks for your help.
I have resolved this problem. Because i missed user &amp; remotename options, so the
PAP authentication was not completed. I guess that ppp on the isp was terminated
then, and all messages sent by my pppd was sent back.
</STRONG></P>
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