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<A HREF="http://www.linuxgazette.com/">
<IMG ALT="LINUX GAZETTE" SRC="../gx/2002/lglogo_200x41.png"
WIDTH="200" HEIGHT="41" border="0"></A>
<BR CLEAR="all">
<SMALL>...<I>making Linux just a little more fun!</I></SMALL>
</TD><TD>
<center>
<BIG><BIG><STRONG><FONT COLOR="maroon">More 2&cent; Tips!</FONT></STRONG></BIG></BIG><BR>
<!-- BEGIN tips -->
<STRONG>By <A HREF="mailto:linux-questions-only@ssc.com">The Readers of <i>Linux Gazette</I></A></STRONG></BIG>
</TD></TR>
</TABLE>
<P>
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<center><STRONG>See also: The Answer Gang's
<a href="../tag/kb.html">Knowledge Base</a>
and the <i>LG</i>
<a href="http://www.linuxgazette.com/search.html">Search Engine</a></STRONG>
</center><HR>
<UL>
<!-- index_text begins -->
<li><A HREF="#tips.1"
><strong>linux baby clothes?</strong></a>
<li><A HREF="#tips.2"
><strong>bookmark conversion</strong></a>
<li><A HREF="#tips.3"
><strong>Cups</strong></a>
<li><A HREF="#tips.4"
><strong>DOS functions in Linux' gcc?</strong></a>
<li><A HREF="#tips.5"
><strong>Internet by call in USA?</strong></a>
<li><A HREF="#tips.6"
><strong>[GL] nis problem</strong></a>
<li><A HREF="#tips.7"
><strong>Pctel hsp micromodem 56 config.........RedHat 8.0</strong></a>
<li><A HREF="#tips.8"
><strong>Debian upgrade howto</strong></a>
<li><A HREF="#tips.9"
><strong>more verbose and useful assert()</strong></a>
<li><A HREF="#tips.10"
><strong>carrier errors</strong></a>
<li><A HREF="#tips.11"
><strong>architecture</strong></a>
<li><A HREF="#tips.12"
><strong>floppy woes</strong></a>
<li><A HREF="#tips.13"
><strong>firewalls</strong></a>
<li><A HREF="#tips.14"
><strong>Internet Cafe ?</strong></a>
<li><A HREF="#tips.15"
><strong>Making IPTABLES complain...</strong></a>
<li><A HREF="#tips.16"
><strong>iso</strong></a>
<li><A HREF="#tips.17"
><strong>mcrypt</strong></a>
<li><A HREF="#tips.18"
><strong>how to config a modem to received call</strong></a>
<li><A HREF="#tips.19"
><strong>mounting cd</strong></a>
<li><A HREF="#tips.20"
><strong>linux S/W ? for movies</strong></a>
<li><A HREF="#tips.21"
><strong>mouse driver, rather not</strong></a>
<li><A HREF="#tips.22"
><strong>root like permissions</strong></a>
<li><A HREF="#tips.23"
><strong>UPS Problems..</strong></a>
<li><A HREF="#tips.24"
><strong>To find out what's in an RPM</strong></a>
<!-- index_text ends -->
</UL>
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<P> <A NAME="tips.1"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">linux baby clothes?</FONT></H3>
Tue, 8 Apr 2003 12:40:53 +0200
<BR>Robos (<a href="mailto:linux-questions-only@ssc.com?cc=koopzy@optushome.com.au&cc=robos@muon.de&subject=%20Re%3A%20%5BLG%2090%5D%202c%20Tips%20%231">the <em>LG</em> Answer Gang</a>)
<BR>Question by J.Cooper (koopzy from optushome.com.au)
<P><STRONG>
gday - how'd it go with the inquiry about Linux baby clothes?
</STRONG></P>
<P><STRONG>
<a href="../issue67/lg_mail67.html#wanted/5">Help Wanted #5, Issue 67</a>
</STRONG></P>
<blockquote><DL><DT>
How about this one here:
<DD><A HREF="http://www.thinkgeek.com/tshirts/kids"
>http://www.thinkgeek.com/tshirts/kids</A>
</DL></blockquote>
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<P> <A NAME="tips.2"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">bookmark conversion</FONT></H3>
Tue, 08 Apr 2003 11:03:48 +0300
<BR>Miron Brezuleanu (<a href="mailto:linux-questions-only@ssc.com?cc=mbrezu@home.ro&subject=%20Re%3A%20%5BLG%2090%5D%202c%20Tips%20%232">mbrezu from home.ro</a>)
<P>
Hi,
</P>
<P>
I have a www browser bookmark conversion problem (and a partial answer
<IMG SRC="../gx/dennis/smily.gif" ALT=":)"
height="24" width="20" align="middle"> ). I'm currently using Opera as a browser but I wanted to also use
Konqueror. As always, there is an issue with the bookmarks: it's
difficult to "port" them. After one hour of groping and hacking I
managed to write a little script that does the opera-&gt;konqueror port.
But it is ugly and it doesn't work in the other direction.
</P>
<P>
Do you know of such bookmark converting apps/scripts (on linux!)?
Konqueror (in kde 3.0) seems to know how to import/export bookmarks to
netscape and mozilla, but not more.
</P>
<P>
I hope this qualifies as a Linux question
<IMG SRC="../gx/dennis/smily.gif" ALT=":)"
height="24" width="20" align="middle"> . It's an all platform
issue, but that doesn't mean it's not linux, right ?
<IMG SRC="../gx/dennis/smily.gif" ALT=":)"
height="24" width="20" align="middle">
</P>
<P>
I included my partial-answer-script. Maybe someone can use it
<IMG SRC="../gx/dennis/smily.gif" ALT=":)"
height="24" width="20" align="middle"> . I
don't really know perl, my script is probably very ugly but it worked
for me. It's a filter, you have to use redirection and then copy the
output file to the konqueror bookmark file.
</P>
<P>
Thanks,
<BR>Miron Brezuleanu
</P>
<p align="center">See attached <tt><a href="misc/tips/op2konq.pl">op2konq.pl</a></tt></p>
<BLOCKQUOTE>
[K.-H.]
Hmm... opera has some bookmark export variants too.
</BLOCKQUOTE>
<BLOCKQUOTE>
Like file-export-bookmarks_as_html looks like a very much universal export
format if you simply load that html page and klick on the bookmark you want.
</BLOCKQUOTE>
<BLOCKQUOTE>
As I remember netscape bookmarks are a simple html layout as well which you
can directly load as an html-page.
</BLOCKQUOTE>
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<P> <A NAME="tips.3"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">Cups</FONT></H3>
Wed, 9 Apr 2003 12:33:11 -0700
<BR>Rick Moen (<a href="mailto:linux-questions-only@ssc.com?cc=leonc@workforce.co.za&cc=rick@linuxmafia.com&subject=%20Re%3A%20%5BLG%2090%5D%202c%20Tips%20%233">the <em>LG</em> Answer Gang</a>)
<BR>Question by Leon Coertzen (leonc from workforce.co.za)
<P><STRONG>
This is a multi-part message in MIME format.
</STRONG></P>
<P><STRONG>
------=_NextPart_000_0030_01C2FDD5.E597FE00
Content-Type: text/plain;
</STRONG></P>
<P><STRONG>
charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
</STRONG></P>
<P>
I'm sure you're unaware of this, but you sent your message
with extraneous MIME headers like the foregoing, and with your entire
message printed a second time in HTML. Please change your mailer's
settings to stop it from doing this. Instructions are here:
<A HREF="http://expita.com/nomime.html#outlook5"
>http://expita.com/nomime.html#outlook5</A>
</P>
<P>
For more information, please see
(<A HREF="../tag/ask-the-gang.html#non_text"
>http://www.linuxgazette.com/tag/ask-the-gang.html#non_text</A>)
</P>
<blockquote><font color="#000066">Normally I leave this part out. However, since I note that Rick has had
to utter this little macro an awful lot of times this month, I figured
I'd help a few souls out there by seeing it get mentioned. The answer
in this case is tiny - so this brings it up to a whole Two Cents worth
:D
-- Heather</font></blockquote>
<P><STRONG>
How do you set printing priorities with cups?
</STRONG></P>
<P><CODE>
Using the -p option:
</CODE></P>
<P><CODE>
$ /usr/bin/lp -d LaserJet -p 90 foo
</CODE></P>
<P>
...gives the job of printing file foo a priority of 90 out of 100.
Default priority level is 50.
</P>
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<P> <A NAME="tips.4"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">DOS functions in Linux' gcc?</FONT></H3>
Wed, 23 Apr 2003 21:50:38 +0100
<BR>Jimmy O'Regan (<a href="mailto:linux-questions-only@ssc.com?cc=sarifali_007@rediffmail.com&cc=jimregan@o2.ie&subject=%20Re%3A%20%5BLG%2090%5D%202c%20Tips%20%234">the <em>LG</em> Answer Gang</a>)
<BR>Question by Arif Ali Saiyed (sarifali_007 from rediffmail.com)
<P><STRONG>
Respected sir/ madam ,
</STRONG></P>
<P><STRONG>
can i use execute interrupt 11h and 13 h as i
can use in TURBO C using int86 function , plz give some
inforamtion or notes how to do that in linux using gcc
thanking you in advance
</STRONG></P>
<P>
I'm not sure if it's possible in the same way it is in DOS, but it's
definitely not the done thing. Wine (<A HREF="http://www.winehq.com"
>http://www.winehq.com</A>) has code in
its DOS emulation dll, which you could probably use in a similar way.
Look in wine/msdos/ and wine/dlls/winedos
</P>
<P>
Int 11 is equipment check and 13 is disk services, right? For int 11,
you might try using Discover
(<A HREF="http://www.progeny.com/products/discover"
>http://www.progeny.com/products/discover</A>). For int 13, you'd need to
be more specific
</P>
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<P> <A NAME="tips.5"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">Internet by call in USA?</FONT></H3>
Thu, 10 Apr 2003 12:39:55 +0200
<BR>Uwe Altmann (<a href="mailto:linux-questions-only@ssc.com?cc=matthi@gmx.li&cc=uwe.altmann@web.de&subject=%20Re%3A%20%5BLG%2090%5D%202c%20Tips%20%235">uwe.altmann from web.de</a>)
<BR>Question by matthi (matthi from gmx.li)
<blockquote><font color="#000066">In response to
<a href="http://www.linuxgazette.com/issue89/lg_mail.html#wanted.6">Help Wanted #6, Issue 89.</a>
-- Heather</font></blockquote>
<P>
Hi matthi
</P>
<P>
In US, visit the next public library - there are some PCs in every
public library with which you can access internet (and therefore via
webmailer your mail) for free.
Also, many Hotels/Motels have free web-access by LAN or, al least, an PC
with freee webaccess (motels with moderate prices too, afaik motel 8,
motel 6) - you can choose your accomodation by that.
</P>
<!-- end 5 -->
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<P> <A NAME="tips.6"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">[GL] nis problem</FONT></H3>
Wed, 23 Apr 2003 15:11:47 -0700
<BR>Dan Wilder (<a href="mailto:linux-questions-only@ssc.com&cc=dan@ssc.com&subject=%20Re%3A%20%5BLG%2090%5D%202c%20Tips%20%236">SSC sysadmin</a>)
<BR>Question by glue-list (<a href="http://www.ssc.com:8080/glue/">http://www.ssc.com:8080/glue/</a>)
<blockquote><font color="#000066">The author here - a member of the GLUE list, contacts for "Groups of
Linux Users Everywhere" - was really hoping he was wrong, but this is how the
dreaded YP stuff really works. A tip for all who have to deal with NIS.
-- Heather</font></blockquote>
<P><STRONG>
1) I search various web-sites, but I cann't find this.my nis-server and
nis-client works properly. ypbind at client detects the nis-server also.
yp.conf,network files all r fully configured in client and server both.
"ypcat passwd" also displays the user info in both client &amp; server. But when
I create any new user at nis-server,I can get user-info by running "ypcat
passwd" only when then I execute make command in <TT>/var/yp</TT> or "ypinit -m" in
<TT>/lib/usr/yp</TT> folder AGAIN.I want to know that IS it Required to execute MAKE
COMMAND AGAIN &amp; AGAIN When any New User Created ?
</STRONG></P>
<P>
In a word, yes.
</P>
<!-- end 6 -->
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<P> <A NAME="tips.7"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">Pctel hsp micromodem 56 config.........RedHat 8.0</FONT></H3>
22 Apr 2003 23:26:58 +0530
<BR>Kapil Hari Paranjape (<a href="mailto:linux-questions-only@ssc.com?cc=vivek_ravindranath@softhome.net&cc=kapil@imsc.res.in&subject=%20Re%3A%20%5BLG%2090%5D%202c%20Tips%20%237">the <em>LG</em> Answer Gang</a>)
<BR>Question by Vivek Ravindranath (vivek_ravindranath from softhome.net)
<P><STRONG>
Hi there,
</STRONG></P>
<P><STRONG>
I wonder if this would be useful to some of you out there.I had
some problems configuring my Pctel PCI modem.After a lot of searching I
found a driver at linmodems.org.The compilation went on perfectly but
when I tried to load the modules with insmod I could not load the
modules and it would display that the module is compiled with GCC 3 and
hence cannot be loaded.
</STRONG></P>
<BLOCKQUOTE>
[Kapil]
Thanks for your hints ...
</BLOCKQUOTE>
<BLOCKQUOTE>
Note that many distro kernels are compiled with gcc 2.95 (in fact I
don't believe I have successfully compiled a kernel with gcc &gt;= 3.0).
</BLOCKQUOTE>
<BLOCKQUOTE>
Thus a possibly better solution is to install gcc-2.95 and compile kernel
modules using that.
</BLOCKQUOTE>
<BLOCKQUOTE>
An alternative is to re-compile your kernel with gcc 3 and then you can
use modules compiled with gcc 3 as well.
</BLOCKQUOTE>
<P><STRONG>
If you are facing the same problem do this....
</STRONG></P>
<P><STRONG>
1.At the console type
</STRONG></P>
<pre><strong>insmod -f pctel
insmod -f ptserial
</strong></pre>
<P><STRONG>
(instructions on installing the modules can be found
in the readme file found with the package).
(If you are using the same tarball from linmodems.org
i.e.,pctel-0.9.6.tar.gz you have to type commands as it is).
You will see some messages but it does not matter much.
</STRONG></P>
<BLOCKQUOTE>
[Kapil]
Generally speaking, I would do an "insmod -f" only if I was in a hurry
or if I couldn't even boot-to-fix witout it. But it should never be
allowed to be a "permanent" solution.
</BLOCKQUOTE>
<P><STRONG>
2.If you are using KPPP to connect to the internet do this.....
create a new connection,fill in the connection details and other things.
Then go to the modem tab and click on modem commands.In the section
named initialization string 2 give the following "AT&amp;FX1&amp;C1" and press
ok.
</STRONG></P>
<P><STRONG>
3.Instead of loading the modules each time the above given commands you
create a script which you can execute before starting kppp.
I can't assure that it is going to work,but you might as well give it a try.
</STRONG></P>
<P><STRONG>
Hope this will help.
Vivek.
</STRONG></P>
<BLOCKQUOTE>
[Kapil]
Me too.
</BLOCKQUOTE>
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<P> <A NAME="tips.8"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">Debian upgrade howto</FONT></H3>
Sun, 13 Apr 2003 01:47:20 -0700
<BR>Rick Moen (<a href="mailto:linux-questions-only@ssc.com?cc=arjun2@hotpop.com&cc=rick@linuxmafia.com&subject=%20Re%3A%20%5BLG%2090%5D%202c%20Tips%20%238">the <em>LG</em> Answer Gang</a>)
<BR>Question by ARJUN (arjun2 from hotpop.com)
<P><STRONG>
how to upgrade the existing debian version without reinstalling ?
(for an ex. potato to woody)
</STRONG></P>
<P>
<A HREF="http://www.debian.org/">Debian</A>'s built-in upgrade process is controlled by the
<TT>/etc/apt/sources.list</TT> file and by the apt-get package-retrieval utility.
sources.list specifies where to look for new packages (Web or ftp sites,
CD-ROMs, hard drive directories, etc.), and apt-get fetches both
available-package catalogues and the packages themselves. Your
sources.list probably looks like this:
</P>
<code>deb <A HREF="http://http.us.debian.org/debian"
>http://http.us.debian.org/debian</A> stable main non-free contrib
<br>deb <A HREF="http://non-us.debian.org/debian-non-US"
>http://non-us.debian.org/debian-non-US</A> stable/non-US main contrib non-free
<br>deb <A HREF="http://security.debian.org"
>http://security.debian.org</A> stable/updates main contrib non-free
</code>
<P>
Notice the word "stable". At the time you installed Debian, "stable"
referred to 2.2/potato. These days, "stable" has progressed to
3.0/woody: The alias name "oldstable" can still be used to refer to
potato, or you can just use the name potato.
</P>
<P>
That is, <EM>if</EM> the machine you're talking about has Internet access, you
can upgrade in two stages, like this.
</P>
<P>
1. Edit sources.list to refer to "potato" by name:
</P>
<code>deb <A HREF="http://http.us.debian.org/debian"
>http://http.us.debian.org/debian</A> potato main non-free contrib
<br>deb <A HREF="http://non-us.debian.org/debian-non-US"
>http://non-us.debian.org/debian-non-US</A> potato/non-US main contrib non-free
<br>deb <A HREF="http://security.debian.org"
>http://security.debian.org</A> potato/updates main contrib non-free
</code>
<P>
As root, retrieve the latest available-packages list for potato:
</P>
<P><CODE>
# apt-get update
</CODE></P>
<P>
Now, upgrade all installed packages to the latest for the potato series:
</P>
<P><CODE>
# apt-get dist-upgrade
</CODE></P>
<P>
2. Re-edit sources.list to refer to "stable" (which is now 3.0/woody):
</P>
<P><BLOCKQuote>
deb <A HREF="http://http.us.debian.org/debian"
>http://http.us.debian.org/debian</A> stable main non-free contrib
deb <A HREF="http://non-us.debian.org/debian-non-US"
>http://non-us.debian.org/debian-non-US</A> stable/non-US main contrib non-free
deb <A HREF="http://security.debian.org"
>http://security.debian.org</A> stable/updates main contrib non-free
</BLOCKQuote></P>
<P><CODE>
# apt-get update
<BR># apt-get dist-upgrade
</CODE></P>
<P>
The point of doing the upgrade in two stages is to avoid introducing
dramatic version differences, all at once.
</P>
<P>
However, it may be that pulling down a hundred or so packages from the
<EM>Internet</EM> isn't practical. If so, you can acquire a set of Official
Debian 3.0r1 CD-ROMs. The full set is 7 CDs. (You don't need to get
all seven, if you don't want to.) To register them in sources.list,
first comment out any existing "deb" lines in that file, and then run
the apt-cdrom utility once for each CD. Then:
</P>
<P><CODE>
# apt-get update
<BR># apt-get dist-upgrade
</CODE></P>
<P>
That's just about all there is to it. Make sure you take note of any
warnings or advisories shown to you during the upgrade process.
</P>
<HR width="10%" align="center"><P><STRONG>
I was looking for this a long. and U have given me the solution.
I know that "thanks a lot" is not enough. any how wish u my best wishes -
<IMG SRC="../gx/dennis/smily.gif" ALT=";)"
height="24" width="20" align="middle">))
</STRONG></P>
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<P> <A NAME="tips.9"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">more verbose and useful assert()</FONT></H3>
Sun, 6 Apr 2003 12:32:02 -0700 (PDT)
<BR>Mike Sharov (<a href="mailto:linux-questions-only@ssc.com?cc=msharov@talentg.com&subject=%20Re%3A%20%5BLG%2090%5D%202c%20Tips%20%239">msharov from talentg.com</a>)
<P>
In reference to the <TT> assert()</TT> macro that good
programmers use to catch bugs that should be fixed before
the user sees them -
</P>
<P>
Unfortunately, when a programmer debugs
somebody else's code, an assert failure may be rather
difficult to interpret. What does assert(p == NULL); failure
mean? You will not know until you look at the source code at
that point and try to understand what's going on. But what
if the assert was changed to:
</P>
<blockquote><pre>assert (p == NULL &amp;&amp; "Please deallocate your GC handle before allocating a new one");
</pre></blockquote>
<P>
Now the programmer can read the message, which will be printed
along with the rest of the stuff in the assert, smack himself
on the forehead and shout "doh. I know where the problem is!"
The assert works because the string pointer is always non-zero
and if p == NULL, will not cause the assert to fail.
</P>
<P>
This seems pretty obvious, now that I have figured it out, but
I have never seen this technique used in any piece of code. The
effect can be achieved by using a custom assert library, but why
introduce a dependency when you don't have to?
</P>
<P><STRONG>
[Jimmy O'Regan]
Would it not be better to use
</STRONG></P>
<pre><strong>if (!assert (p == NULL))
fprintf (stderr, "Please deallocate your GC handle before allocating a new one");
</strong></pre>
<BLOCKQUOTE>
[Didier Heyden]
Nope; <TT> assert()</TT> actually aborts the program if its argument is 'false.'
This means that your own message would never be printed, even if the 'p'
variable were NULL. Instead, you'd see something like:
</BLOCKQUOTE>
<blockquote><pre>PROGNAME: SOURCE.c:31415: FUNCTION: Assertion `p == NULL' failed.
Aborted
</pre></blockquote>
<BLOCKQUOTE>
then the program would terminate (and possibly dump core).
</BLOCKQUOTE>
<BLOCKQUOTE>
OTOH, with Mike's method you'd get a message similar to:
</BLOCKQUOTE>
<blockquote><pre>PROGNAME: SOURCE.c:27182: FUNCTION: Assertion `p == NULL &amp;&amp;
"Please deallocate your GC handle..."' failed.
Aborted
</pre></blockquote>
<BLOCKQUOTE>
The reason his solution works is that a string constant in C (even
an "empty" one) always evaluates as a 'true' condition (a non-null
memory reference indeed).
</BLOCKQUOTE>
<BLOCKQUOTE>
Another advantage of sticking with "simple" <TT> assert()</TT> macro calls is
that you can disable all of them at once, merely by #defining the
NDEBUG macro at compilation time. In that case, all <TT> assert()</TT>
instructions will expand to nothing at all.
</BLOCKQUOTE>
<P><STRONG>
[Jimmy]
(or similar, apologies for my rusty C)
</STRONG></P>
<BLOCKQUOTE>
[Didier]
Naaah.
<IMG SRC="../gx/dennis/smily.gif" ALT=":)"
height="24" width="20" align="middle"> I wish I could remember the specific syntactical issues of
my own rusty programming languages as precisely as you do. Expect my
over-volatile memory to bring back sooner or later awful games of 2^^7
errors such as
</BLOCKQUOTE>
<blockquote><pre>#/usr/bin/perl -W
using strict;
my despair = {'Why', 'the heck', 'doesn't this', 'work'}
for each (@cry in $despair) { echo @cry, " (sob) " }
</pre></blockquote>
<BLOCKQUOTE>
(Don't laugh: it's based on countless true stories).
</BLOCKQUOTE>
<!-- end 9 -->
<!-- .~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~. -->
<P> <A NAME="tips.10"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">carrier errors</FONT></H3>
Wed, 23 Apr 2003 12:28:18 -0400
<BR>Kapil Hari Paranjape (<a href="mailto:linux-questions-only@ssc.com?cc=kuhman@myrealbox.com&cc=kapil@imsc.res.in&subject=%20Re%3A%20%5BLG%2090%5D%202c%20Tips%20%2310">the <em>LG</em> Answer Gang</a>)
<BR>Question by Harry (kuhman from myrealbox.com)
<P><STRONG>
I came across your "Answer guy" site while searching for info
on ifconfig errors. Unfortunately, it did not help with my
problem, but since you provide an e-mail link, I'm not too
proud to ask.
</STRONG></P>
<P><STRONG>
The question I'm trying to understand is "what are "carrier"
errors. I'm getting "carrier" errors on 100% of my my TX packets
and can't connect to the rest of the network, but the man pages
for ifconfig don't tell me what the errors are and I'm at a loss
so far to find information on this.
</STRONG></P>
<BLOCKQUOTE>
Carrier errors is jargonese for Cable fault. Please check the cable you
are using (try a different one if you have one). Of course it could also
be a loose contact problem.
</BLOCKQUOTE>
<BLOCKQUOTE>
Carrier = Signal Carrier = standing wave on which signals are
transmitted using "modulation". That's about as much as I remember from
by College course in Electronics.
</BLOCKQUOTE>
<P><STRONG>
The complete problem is that I'm running both WinXP and Linux
(Knoppix booted from CD) on an HP notebook. Knoppix used to boot
and connect to the network fine, but now it has stopped working!
I'm running strictly from CD, no install or configuration
information on my system, just the normal Knoppix auto-
configuration that worked fine on the hardware before, yet now
for reasons unknown I get these carrier errors and can not
transmit anything on the network (sniffing the wire confirms
that nothing is going out). Obviously I can no longer get my
network settings with DHCP (which also used to work fine on
my local network for this computer), but I cannot manually
configure the card to work either. Do you have any insight to
what might cause this?
</STRONG></P>
<HR width="10%" align="center"><P><STRONG>
Thanks. Unfortunately, in this case the "carrier errors" are not cable
errors. Here are the details that confirm this:
</STRONG></P>
<P><STRONG><BLOCKQuote>
The hardware works 100% correctly under WinXP, including sniffing the
cable and seeing absolutely no errors in a large number of packets.
</BLOCKQuote></STRONG></P>
<P><STRONG>
The hardware used to work under Linux (Knoppix booted from CD) but
no longer does, even with the very same bootable CD. There are no
packets getting out onto the cable at all, again confirmed by sniffing
the cable.
</STRONG></P>
<P><STRONG>
A completely different cable was also used to route the notebook
computer to a separate hub where the packets could be watched by
another computer. Still no packets were on the wire.
</STRONG></P>
<BLOCKQUOTE>
I wrote earlier:
Carrier = Signal Carrier = standing wave ...
</BLOCKQUOTE>
<BLOCKQUOTE>
So at least I feel partially vindicated. There is no standing wave hence
no signal
<IMG SRC="../gx/dennis/smily.gif" ALT=":-)"
height="24" width="20" align="middle">
</BLOCKQUOTE>
<P><STRONG>
Apparently other Linux issues can manifest themselves as carrier errors,
but I have not yet been able to determine what counts as a carrier error
in Linux.
</STRONG></P>
<BLOCKQUOTE>
Let's apply Occam's razor here based on the fact the "it used to work
with the same Knoppix CD". What could have changed?
</BLOCKQUOTE>
<blockQuote><ol>
<LI>Not the CD. And hence not Linux or the software that comes with it.
<LI>Not the cable (this has been checked by you).
<LI>Not the hardware (it works under that other OS so its not critically
damaged).
</ol></blockQuote>
<BLOCKQUOTE>
Thus the problem has to be with the remaining "soft" component. That is
BIOS/flash settings. Some Network cards store some settings. You could
examine these settings using the <a href="http://www.scyld.com/diag/">mii-tools</a>.
Additionally, check whether
you have made some changes to the BIOS.
</BLOCKQUOTE>
<HR width="10%" align="center"><P><STRONG>
I just wanted to give you some feedback. Thanks very much for the reference
to mii-rtools, it really helped. It looks almost certain at this point that
Microsoft's "security updates" are changing NIC configuration eeproms. And,
of course, Microsoft knows not to use the bad configuration and works fine
with the change, but another OS like Linux that trusts that the configuration
in the eeprom is what the manufacturer or user wants fails. I've found
several other users that have been trying to figure out what happened, why
their CD used to work fine but now fails on the same system. We all accepted
Microsoft "security updates". We are now trying to get a test done with
some networking tools that can watch the content of the eeprom and catch
when it changes, so I expect to have evidence to support this soon.
</STRONG></P>
<blockquote><font color="#000066">I'm pretty sure it can - I know a
dyed-in-the-wool linuxer who currently
has to consider his happy little Orinoco family wireless pcmcia card a piece
of junk because a "helpful" Microsoft update has put it into a state
that Linux and BSD tools don't seem to be able to get it out of. Of
<EM>course</EM> it works fone in the other OS. Grrr.
-- Heather</font></blockquote>
<!-- end 10 -->
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<P> <A NAME="tips.11"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">architecture</FONT></H3>
Wed, 9 Apr 2003 10:51:11 -0700
<BR>Rick Moen (<a href="mailto:linux-questions-only@ssc.com?cc=rick@linuxmafia.com&subject=%20Re%3A%20%5BLG%2090%5D%202c%20Tips%20%2311">the <em>LG</em> Answer Gang</a>)
<P><STRONG>
I have seen that different linux architecture are present based on different
processor architecture. like i386, i586, i686 etc. what are these &amp; how to
know the architecture of my processor ?
</STRONG></P>
<P>
JK, Linux provides an excellent facility for this sort of thing, in the
form of <TT>/proc/cpuinfo.</TT> Here's the one from the server I'm mailing this
from:
</P>
<blockquote><font color="#000066">For those ignorant of or who simply are happy to avoid the text editor
vi (or its friendlier cousin vim) :r is a command which, when issued
from command mode, will read what comes after it. :r! runs a command,
which can be nice for inhaling man page fragments, too. Making this a
Three Cent Tip...
-- Heather</font></blockquote>
<blockquote><pre>:r /proc/cpuinfo
processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 7
model name : Pentium III (Katmai)
stepping : 2
cpu MHz : 498.755
cache size : 512 KB
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 2
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 mmx fxsr sse
bogomips : 996.14
</pre></blockquote>
<P>
There. More than you really wanted to know about the host's CPU. Of
course, the above gives information about the <EM>hardware</EM>. The machine's
kernel may or may not have been compiled with appropriate optimistions,
though that will generally be included in the output of uname -r (kernel
release).
</P>
<BLOCKQUOTE>
[Pradeep]
i386, i586, i686 are different kind of processor architectures developed
by intel. The following link has some info about this:
<A HREF="http://www.rebourne.org/chiparch.htm"
>http://www.rebourne.org/chiparch.htm</A>
</BLOCKQUOTE>
<blockquote><font color="#000066">In the terminology of the hardware hackers, these are considered the same
architecture (32 bit Intel, "i386" if you're looking in the kernel source
tree). There are a few optimizations, but the <EM>way</EM> they think is similar.
Contrast a Sparc, a Strongarm (found in many handhelds), or even Intel's
own ia64 ("Itanium" if you prefer them by name).
-- Heather</font></blockquote>
<!-- end 11 -->
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<P> <A NAME="tips.12"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">floppy woes</FONT></H3>
Mon, 14 Apr 2003 08:11:21 +0530
<BR>Kapil Hari Paranjape (<a href="mailto:linux-questions-only@ssc.com?cc=ursacava@mindspring.com&cc=kapil@imsc.res.in&subject=%20Re%3A%20%5BLG%2090%5D%202c%20Tips%20%2312">the <em>LG</em> Answer Gang</a>)
<BR>Question by Ronald Russell (ursacava from mindspring.com)
<P><STRONG>
I'm running <A HREF="http://www.suse.com/">SuSE</A> 7.1 and Win98 on separate hard drives in a 900 Mhz Celeron
machine. Things were working fine until recently, when I could no longer
access my floppy while in SuSE. The same drive reads and writes perfectly in
Win98. When attempting to mount the floppy either by clicking the desktop
icon, or by typing the command in the terminal, I receive the error
'<TT>/dev/fd0</TT> is not a block device'.
What could have happened to cause this, and what can I do to repair it?
</STRONG></P>
<P>
Some possibilities suggest themselves.
</P>
<blockQuote><ol>
<LI>The device node is not properly created. Run '<tt>ls -l /dev/fd0</tt>' and
check.
<LI>You have a modular floppy driver which is not loaded. Run
'<tt>/sbin/lsmod</tt>' to check whether the driver is loaded.
</ol></blockQuote>
<BLOCKQUOTE>
[Didier Heyden]
A third possibility is that your floppy disks and/or drive are actually
defective. A '<tt>mount</tt>' command issued on <TT>/dev/fd0</TT> (assuming that this block
device file and the kernel modules are all set up properly) will first
try to access the disk's boot sector. If <EM>any</EM> I/O error occurs then,
the 'mount' will fail with the error message you mention.
</BLOCKQUOTE>
<BLOCKQUOTE>
Take a look at the system log files (usually <TT>/var/log/messages</TT>, but you
can also use the 'dmesg' command). Check whether errors like
</BLOCKQUOTE>
<BLOCKQUOTE><code>
[...] kernel: end_request: I/O error, dev 02:00 (floppy), sector 0
</code></BLOCKQUOTE>
<BLOCKQUOTE>
are present; if so, try to mount a few other floppy disks. If the system
keeps producing an error similar to the above, chances are that you
will have to replace your floppy drive very soon -- in particular if
the very same diskettes are correctly mounted and read on some other
(Linux) box.
</BLOCKQUOTE>
<BLOCKQUOTE>
There was a time when such a problem could be caused by a drive head
"misalignment", but I'm not sure it's still the case these days.
</BLOCKQUOTE>
<blockquote><font color="#000066">I think it can be; also, depending on your console setup, you might not
have to dig in the logs to see these complaints, as they might spew on
your console rather vocally.
</font></blockquote>
<blockquote><font color="#000066">First thing I'd check is whetehr there's a file in your /dev/ area that
used to be your floppy node, fd0 or any of the others starting with fd.
-- Heather</font></blockquote>
<BLOCKQUOTE>
I don't know much about WinXX, though I guess that that other OS either
does more retries before giving up or is too lax regarding sanity
checks prior to granting access to the user (I can't help favoring the
latter explanation).
</BLOCKQUOTE>
<!-- end 12 -->
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<P> <A NAME="tips.13"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">firewalls</FONT></H3>
Wed, 09 Apr 2003 17:52:39 +0200
<BR>Didier Heyden (<a href="mailto:linux-questions-only@ssc.com?cc=deepaselvaraju@yahoo.co.in&cc=fakir@teledisnet.be&subject=%20Re%3A%20%5BLG%2090%5D%202c%20Tips%20%2313">the <em>LG</em> Answer Gang</a>)
<BR>Question by deepa lakshmi (deepaselvaraju from yahoo.co.in)
<P>
On Wed, 9 Apr 2003 13:48:45 +0100 (BST), deepa lakshmi wrote:
</P>
<P><STRONG>
hello
</STRONG></P>
<P>
Hi,
</P>
<P><STRONG>
i have a firewall machine .i also have a machine with ip 192.168.1.7
behind the firewall.
</STRONG></P>
<P><STRONG>
i added prerouting rules to forward incoming request to internal web
servers which are behind firewall.
</STRONG></P>
<P><STRONG>
now i want machine with ip 192.168.1.7 to have
internet access through firewall.
i have tried with this rules.but no resonse fron machine
rules are
</STRONG></P>
<pre><strong>-A POSTROUTING -o eth0 -j SNAT --to-source 202.54.100.54
-A FORWARD -i eth1 -j ACCEPT
-A FORWARD -m state --state ESTABLISHED,RELATED -j ACCEPT
</strong></pre>
<P><STRONG>
but it's not working.
</STRONG></P>
<P><DL><DT>
First, let me suggest to you to read carefully:
<DD><A HREF="../tag/ask-the-gang.html#doesnt_work"
>http://www.linuxgazette.com/tag/ask-the-gang.html#doesnt_work</A>
</DL></P>
<P>
before saying that. Since we have no means to guess what actually happens
on your system when you try the firewall rules you mention, you cannot
expect us to be able to provide much help in exchange for so little
information as you've given.
</P>
<P>
For example, is the above ruleset complete, or is it (as is more likely)
only a subset of the actual rules you're using? Are these rules accepted
at all when you enter them on the command line? What do the log files on
your firewall machine say? Did you try a packet sniffer such as "tcpdump"
or "ethereal" on its network interfaces? Did you make sure all required
kernel modules have been compiled, installed and are actually loaded?
Is "IPv4 forwarding" enabled? etc, etc.
</P>
<P>
I'm not an "iptables" expert myself, but I think the "-t &lt;table&gt;" option
is not an unimportant one.
</P>
<P>
Here's a precious resource about setting up a Netfilter/iptables
firewall. It covers pretty much everything (including source NAT and
masquerading) and has a number of useful examples:
</P>
<P><BLOCKQuote>
<A HREF="http://iptables-tutorial.frozentux.net/iptables-tutorial.html"
>http://iptables-tutorial.frozentux.net/iptables-tutorial.html</A>
</BLOCKQuote></P>
<P>
&lt;solemnly&gt;
Beware that in order to set up a firewall in the Right Way, you
must definitely know what you're doing. Help yourself. Googlesearch.
Read howtos, tutorials and examples; once you have understood them,
give them a try. Observe the results carefully. Then -- only then --
ask a <EM>precise</EM> question.
<IMG SRC="../gx/dennis/smily.gif" ALT=":)"
height="24" width="20" align="middle">
&lt;/solemnly&gt;
</P>
<BLOCKQUOTE>
[Jason Creighton]
Well, a problem I see is that for the SNAT rule, you need to specify the
table, like this:
</BLOCKQUOTE>
<BLOCKQUOTE><BLOCKQUOTE><CODE>
-t nat -A POSTROUTING -o eth0 -j SNAT --to-source 202.54.100.54
</CODE></BLOCKQUOTE></BLOCKQUOTE>
<BLOCKQUOTE>
All the NAT rules go in the (guess what?) "nat" table. The default table is
'filter', which is used when no table is specified.
</BLOCKQUOTE>
<!-- end 13 -->
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<P> <A NAME="tips.14"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">Internet Cafe ?</FONT></H3>
Tue, 08 Apr 2003 20:54:43 +0100
<BR>Jimmy O'Regan (<a href="mailto:linux-questions-only@ssc.com?cc=wbannon@nadf.org&cc=jimregan@o2.ie&subject=%20Re%3A%20%5BLG%2090%5D%202c%20Tips%20%2314">the <em>LG</em> Answer Gang</a>)
<BR>Question by Wally Bannon (wbannon from nadf.org)
<P>
Wally Bannon wrote:
</P>
<P><STRONG><BLOCKQuote>
I have a client who is Aboriginal here in Northern ontario looking to
set up a Internet Cafe. There are no location in the city of Thunder Bay.
Can you direct me to where I can get info on " how to set up or
establish an Internet Cafe"
This person is a youth age 25 who can access Gov't funding for
assistance to capitalize the project
</BLOCKQuote></STRONG></P>
<P>
If you want to use some combination of both Linux and Windows clients
controlled by a Linux server, try Zeiberbude:
</P>
<P><BLOCKQuote>
<A HREF="http://zeiberbude.sourceforge.net"
>http://zeiberbude.sourceforge.net</A>
</BLOCKQuote></P>
<P>
If you want Linux clients connecting to a Linux server, you could also
try DireqCafe:
</P>
<P><BLOCKQuote>
<A HREF="http://akinimod.sourceforge.net/icafereal.html"
>http://akinimod.sourceforge.net/icafereal.html</A>
</BLOCKQuote></P>
<P>
This is built for the Linux Terminal Server project:
</P>
<P><BLOCKQuote>
<A HREF="http://www.ltsp.org"
>http://www.ltsp.org</A>
</BLOCKQuote></P>
<P>
If you want Windows clients connecting to a Linux server, try Prepaid
Accounting:
</P>
<P><BLOCKQuote>
<A HREF="http://quozl.netrek.org/ppa"
>http://quozl.netrek.org/ppa</A>
</BLOCKQuote></P>
<P>
If you want Windows clients connecting to a Windows server, you'll have
to try asking somewhere else.
</P>
<BLOCKQUOTE>
[Faber Fedor]
If you go to www.google.com and type in "internet cafe howto" the first
link is back to us -- <A HREF="../issue70/tag/9.html"
>http://www.linuxgazette.com/issue70/tag/9.html</A> !
There are several other good links mentioned there on google.
</BLOCKQUOTE>
<!-- end 14 -->
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<P> <A NAME="tips.15"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">Making IPTABLES complain...</FONT></H3>
Tue, 8 Apr 2003 12:46:53 -0600
<BR>Jason Creighton (<a href="mailto:linux-questions-only@ssc.com?cc=ryujin_ssdt@yahoo.co.uk&cc=androflux@softhome.net&subject=%20Re%3A%20%5BLG%2090%5D%202c%20Tips%20%2315">androflux from softhome.net</a>)
<BR>Question by =?ISO-8859-1?Q?\=CE=B6=BF=C0\?= (ryujin_ssdt from yahoo.co.uk)
<P><STRONG>
I have a little question. I have a iptables rule set that works perfectly. The
problem is that to check if it is working as it has to I have to check the
long log files every some time.
</STRONG></P>
<P><STRONG>
I really would like my laptop to complain when some unauthorized conection is
attempted in real time or when my laptop tries to connect to other host
without me doing it. Much the way Zonealarm complains. I just want the system
to tell me that something strange is going on without me having to see the
logfiles all the time or installing a dedicated IDS (snort).
</STRONG></P>
<P><STRONG>
I think if I can get iptables to send all the dropped packets somewhere a
normal user (not root) can read them, I can grab that data periodically and
display a little alarm with it using maybe karamba?? Any sugestions??
</STRONG></P>
<P><STRONG>
Just a little personal firewall for my desktop, since linux is becoming a
candidate for personal desktop (It is already for me) this feature would be a
good add-on.
</STRONG></P>
<BLOCKQUOTE>
[Jason]
Now, do you want the <EM>data</EM> that the packets contain, or just the packet
headers? The LOG target, will, as you know (if you're reading log files) give
that information. If you really need the data, look into the ULOG target. The
ULOG target sends the packet through a netlink socket to any listening process
in userspace, so you'll need a daemon running to "catch" all those packets.
Search the web for "iptables ULOG target", I haven't done much research into
that method, so I don't know how well it would work.
</BLOCKQUOTE>
<BLOCKQUOTE>
It sounds like you want a pop-up window every time somebody sends you a packet
that iptables drops. That's tricky to implement. Here's a half-way solution:
</BLOCKQUOTE>
<blockquote><pre>tail -f /var/log/syslog | perl -ne 'print "\a$1\n" if (/.*?firewall: *(.*)/)'
</pre></blockquote>
<BLOCKQUOTE>
Assuming you have the --log-prefix option that's given to the LOG target set
to 'firewall:' and that the kernel messages are ending up in <TT>/var/log/syslog</TT>,
this will beep and print the packet details whenever a dropped packet comes
in. You could then leave this running in a terminal. You might also want to
have the 'limit' match on your logging rule, for two reasons:
</BLOCKQUOTE>
<blockQuote><ul>
<LI>Somebody who knows what packets you're logging would flood your logs by
send lots of illegal packets.
<LI>You don't want to be driven crazy by beeps if somebody starts port-scanning
you.
</ul></blockQuote>
<BLOCKQUOTE>
There's probably some better solutions out there, but this works if all you
want is the packet details. Also, it's probably overkill to have perl doing
this.
</BLOCKQUOTE>
<BLOCKQUOTE>
[Matthias]
You could configure your logging client to log your iptables log to a second
file which is group writeable (e.g. group "log") and then parse this log
file.
</BLOCKQUOTE>
<BLOCKQUOTE>
You should search for a <TT>/etc/syslog.conf</TT> or similar. If you have problems you
may ask on the list how to configure your particular logging client (syslogd)
on your distribution.
</BLOCKQUOTE>
<!-- end 15 -->
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<P> <A NAME="tips.16"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">iso</FONT></H3>
Wed, 9 Apr 2003 09:33:00 -0700
<BR>Rick Moen (<a href="mailto:linux-questions-only@ssc.com?cc=emery_558@hotmail.com&cc=rick@linuxmafia.com&subject=%20Re%3A%20%5BLG%2090%5D%202c%20Tips%20%2316">the <em>LG</em> Answer Gang</a>)
<BR>Question by mark (emery_558 from hotmail.com)
<P><STRONG>
i have an iso image how do i burn it to auto run from cd
</STRONG></P>
<BLOCKQUOTE>
[Rick]
You use cdrecord.
</BLOCKQUOTE>
<blockquote><font color="#000066">Yes, cdrecord is available for Windows, albeit usually built under
cygwin, so you might need the cygwin runtime libraries. We also had
a considerable discussion of many avialable types of CD burning software
in a past issue:
<a href="http://www.linuxgazette.com/issue68/tag/11.html">Best of ISO Burning Under Windows</a>
</font></blockquote>
<blockquote><font color="#000066">I've seen that there is software to soft-mount a .iso raw CD image file
as a filesystem under Windows - much like the way Linux and other UNIX
users can "loopback" mount them (so they look like a real disc). Search
Tucows or some other MSwin software archive to find that stuff.
-- Heather</font></blockquote>
<P><STRONG>
its easy cd/dvd.6
</STRONG></P>
<BLOCKQUOTE>
[Rick]
No, when you're mailing a mailing list called <A HREF="mailto:linux-questions-only@ssc.com"
>linux-questions-only@ssc.com</A>,
it most definitely is <EM>not</EM> Roxio Easy CD/DVD 6 for MS-Wind*ws. It's
cdrecord. Get it?
</BLOCKQUOTE>
<blockquote><font color="#000066">Much thrashing by the gang about whether a reader can "get" that we're
going to describe free software to them when they haven't really got
their hands on that first Linux CD yet, snipped. Suffice it to say we
support folks escaping from addiction to the Borg's sugar cubes, but if
you have proprietary software, questions about it <EM>really</EM> ought to go to
its paid support staff.
-- Heather</font></blockquote>
<BLOCKQUOTE>
[Karl-Heinz Herrman]
if it is an true and real iso9660 (plus extensions like Joliet or Rockridge)
yous take it and burn as it is onto a CD. That's it.
</BLOCKQUOTE>
<BLOCKQUOTE>
To add some guesses myself:
</BLOCKQUOTE>
<blockQuote><ul>
<LI>That Roxio thingy is obviously a WinXX program
<LI>"auto run" might mean boot. But then it might mean autorun, which is an
inherent feature of WinXX to execute autorun.inf on inserting a CD (and the
first thing I switch off if I have to put my fingers on a Winbox).
</ul></blockQuote>
<BLOCKQUOTE>
In any case -- the bootability of a CD or the autorun.inf file are either in
the iso or not. If not, it won't "auto run".
</BLOCKQUOTE>
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<P> <A NAME="tips.17"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">mcrypt</FONT></H3>
Wed, 2 Apr 2003 19:58:38 -0500
<BR>Ben Okopnik (<a href="mailto:linux-questions-only@ssc.com?cc=Hans.Borg@Physics.umu.se&cc=ben@callahans.org&subject=%20Re%3A%20%5BLG%2090%5D%202c%20Tips%20%2317">the <em>LG</em> Answer Gang</a>)
<BR>Question by Hans Borg (Hans.Borg from Physics.umu.se)
<P><STRONG>
Have started to play around with mcrypt (my version 2.6.4) mostly
to learn. It works fine, but have a Q:
</STRONG></P>
<P><STRONG><BLOCKQuote>
Having an encrypted file on a (read only) CD, I would like to know
if there is any way to use the CD-file as input only and needed
working files directed to a normal (R/W) diskfile ?
</BLOCKQuote></STRONG></P>
<P><STRONG>
Have tried redirection "mcrypt .... CD-file &gt; HD-file" but mcrypt
reports "read only media". Any tricks to do this ? Currently I have
to copy the CD-file to a R/W-file and then decrypt it.
</STRONG></P>
<P>
Well, running "strace" on "mcrypt" shows it acting like it left its
brain in the dishwasher for too long: it tries (non-optionally) to write
the encrypted file in the same place where the source file is - even if
you issue the request from somewhere else. Duh! Plus, the "-F" switch
that's supposed to make it go to STDOUT does <EM>exactly the same thing</EM> in
the above case. The program is BAD (Broken As Designed.)
</P>
<P>
Here's a solution that works, though:
</P>
<blockquote><pre>cat /mnt/cdrom/foo | mcrypt -F &gt; foo.nc
</pre></blockquote>
<P><STRONG>
Hi Ben,
</STRONG></P>
<P><STRONG>
Thanks a lot. I do recal your name, you have helped out lot in the past.
</STRONG></P>
<P><STRONG>
Your method "cat <TT>/.../foo</TT> | mcrypt .." works fine. NOTE that I am in a learning
phase (as always). Are there better crypt applications around.
</STRONG></P>
<P><STRONG>
Thanks a lot.
</STRONG></P>
<P><STRONG>
Hans.
</STRONG></P>
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<P> <A NAME="tips.18"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">how to config a modem to received call</FONT></H3>
Mon, 21 Apr 2003 16:22:50 +0530 (IST)
<BR>Karl-Heinz Herrmann (<a href="mailto:linux-questions-only@ssc.com?cc=lovett@radoint.com&cc=k.-h.herrmann@fz-juelich.de&subject=%20Re%3A%20%5BLG%2090%5D%202c%20Tips%20%2318">k.-h.herrmann from fz-juelich.de</a>)
<BR>Question by radoint.com (lovett from radoint.com)
<P><STRONG>
i have the problem to config my modem for received login in , i ready
make the test to call out the work, but i can't do for received. becouse
i tried to make a login in for internet service.
</STRONG></P>
<P>
You want to have a look at sendfax and mgetty:
for example at: <A HREF="http://www.leo.org/~doering/mgetty"
>http://www.leo.org/~doering/mgetty</A>
</P>
<P>
mgetty is a daemon which is run by init (see <TT>/etc/init.conf</TT> for
configuration). It will reply to an incoming call on a modem.
</P>
<P>
K.-H.
</P>
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<P> <A NAME="tips.19"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">mounting cd</FONT></H3>
Fri, 28 Mar 2003 08:41:30 -0800
<BR>Dan Wilder (<a href="mailto:linux-questions-only@ssc.com?cc=badrijimale@hotmail.com&cc=dan@ssc.com&subject=%20Re%3A%20%5BLG%2090%5D%202c%20Tips%20%2319">SSC sysadmin</a>)
<BR>Question by BADRI JIMALE (badrijimale from hotmail.com)
<P><STRONG>
hi
</STRONG></P>
<P><STRONG>
i had problem with my unix.
i would like to know how to mount cd on my system which is running redhat
7.0
</STRONG></P>
<P><STRONG>
thank you
</STRONG></P>
<P>
1) Find out which device your CD is attached to. Try
</P>
<blockquote><pre> dmesg | less
</pre></blockquote>
<P>
spacebar takes you forward, q to quit. Look for something
in the messages about a CD. It'll probabably be attached to
<TT>/dev/hdc</TT> or <TT>/dev/hdb.</TT> Unless it's something unusual like
a USB or SCSI CD.
</P>
<P>
As root,
</P>
<blockquote><pre> mkdir /cdrom
</pre></blockquote>
<P>
add a line to <TT>/etc/fstab</TT> that looks like:
</P>
<blockquote><pre> /dev/hdc /cdrom iso9660 defaults,noauto,ro,user 0 0
</pre></blockquote>
<P>
using your favorite text editor, such as vi, emacs,
nedit, kedit, pico, whatever.
</P>
<P>
If the CD is on <TT>/dev/hdd</TT>, use that in place of hdc.
</P>
<P>
As yourself, put a CD in the slot and give command
</P>
<blockquote><pre> mount /cdrom
</pre></blockquote>
<P>
to look at files there
</P>
<blockquote><pre> cd /cdrom
ls
</pre></blockquote>
<P>
and so on.
</P>
<P>
To unmount it,
</P>
<blockquote><pre> umount /cdrom
</pre></blockquote>
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<P> <A NAME="tips.20"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">linux S/W ? for movies</FONT></H3>
Fri, 28 Mar 2003 07:19:33 +0100
<BR>Huibert Alblas (<a href="mailto:linux-questions-only@ssc.com?cc=cave_man@hotpop.com&cc=huibert_alblas@web.de&subject=%20Re%3A%20%5BLG%2090%5D%202c%20Tips%20%2320">huibert_alblas from web.de</a>)
<BR>Question by JK Malakar (cave_man from hotpop.com)
<BLOCKQUOTE>
[Huibert Alblas]
There are some GUIs (Graphical User Interfaces available for these things too:
avidemux (<A HREF="http://avidemux.sourceforge.net"
>http://avidemux.sourceforge.net</A>) (frontend to transcode avi-&gt;everything)
DVD::RIP (<A HREF="http://www.exit1.org/dvdrip"
>http://www.exit1.org/dvdrip</A>) (frontend for transcoding DVD-&gt;everything)
</BLOCKQUOTE>
<BLOCKQUOTE>
Then you are set to go:
</BLOCKQUOTE>
<BLOCKQUOTE><BLOCKQuote>
Safest way is to demultiplex the audio and video from the 3 avi's.
Then concat the 3 audio and video streams, resulting in 1 big audio and 1 big
video stream.
</BLOCKQuote></BLOCKQUOTE>
<BLOCKQUOTE>
[Ben Okopnik]
I've also had good luck with "mplayer" (a wonderful all-around piece of
software); just a couple of days ago, I wanted to grab the audio stream
from a DVD title, so -
</BLOCKQUOTE>
<blockquote><pre>mplayer -dvd 12 -ao:pcm &gt; file.wav
</pre></blockquote>
<BLOCKQUOTE>
Of course, there's the obvious complement of "-vo" for video. For the
available output formats, see
</BLOCKQUOTE>
<blockquote><pre>mplayer -ao help
</pre></blockquote>
<BLOCKQUOTE>
or
</BLOCKQUOTE>
<blockquote><pre>mplayer -vo help
</pre></blockquote>
<BLOCKQUOTE>
Quite an impressive list in both.
</BLOCKQUOTE>
<P><STRONG>
Hi all,
</STRONG></P>
<P><STRONG>
I have downloaded the great <EM>MPlayer</EM> &amp; compiled it under debian.
but whenever I play with
</STRONG></P>
<pre><strong>mplayer /cdrom/movie.dat
</strong></pre>
<P><STRONG>
...MPlayer plays it
within a very small window. maximizing the window can't change the display
area. again there is a synchronization problem between the audio &amp; video
output.
</STRONG></P>
<BLOCKQUOTE>
[Robos]
if you have xvideo support (mplayer -vo xv) try "f" during playback.
Else, try -zoom and|or -fs. If you post your grafic card I can (maybe) tell
you what option to use to get fullscreen.
</BLOCKQUOTE>
<P><STRONG>
it plays sound more quickly than the video. I have also tried with
the option <tt>-autosync n</tt> (where n=1,2 etc), but result is same. could any
one suggest me a solution ?
</STRONG></P>
<P><STRONG>
another newbie question. I have gone through the HTML doc of mencoder. still
the difference between <em>2-pass</em> &amp; <em>3-pass</em> method is not clear to me.
*2-pass* gives better image quality. but what is the advantage of <em>3-pass</em> ?
is it superior to 2-pass. please let me know.
</STRONG></P>
<BLOCKQUOTE>
[Robos]
If I understand it correctly 3 pass does mp3 separately of the video...
</BLOCKQUOTE>
<blockquote><font color="#000066">Anyone who has sufficient info to keep us in sync here? Maybe you could
write an article for us :D
-- Heather</font></blockquote>
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<P> <A NAME="tips.21"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">mouse driver, rather not</FONT></H3>
10 Apr 2003 13:46:09 -0000
<BR>palla ravikiran reddy (<a href="mailto:linux-questions-only@ssc.com?cc=solarflares@rediffmail.com&subject=%20Re%3A%20%5BLG%2090%5D%202c%20Tips%20%2321">solarflares from rediffmail.com</a>)
<P>
Hello,
</P>
<P>
I tried editing the makefile in the drivers/char directory by
removing busmouse.o and other other mice. I then compiled the
kernel and booted using the new image. The mouse was still running
after the reboot.
</P>
<P>
what does this mean? Isn't gpm an application that uses the
busmouse and other mice functions? Only when i kill the gpm daemon
does the mouse stop functioning.
</P>
<P>
Any information would be useful to me.
</P>
<BLOCKQUOTE>
[Joel Mayes]
An .o file is generally an object file, it is the result of the
compilation, so removing one will generally just get it remade
the next time you compile.
</BLOCKQUOTE>
<BLOCKQUOTE>
Also the busmouse.[c|h] files are for an old style serial busmouse
driver, if you have a reasonably modern PC the chances are you have
either a USB or a PS2 mouse.
</BLOCKQUOTE>
<BLOCKQUOTE>
If you want to remove mouse support from the kernel, rather then
deleting files from the kernel source, which could have interesting
results (and you might want to include that support your deleting in the
futher) in "menuconfig" goto "Character Devices" -&gt; "Mice" and disable
support
</BLOCKQUOTE>
<BLOCKQUOTE>
[Heather]
Hi Joel. Ravi, there's more to this that you haven't mentioned, so I'm
going to have to fill in with some guessing.
</BLOCKQUOTE>
<BLOCKQUOTE>
If you didn't tell your bootloader about your new kernel (even if you
succeeded at chopping the mice out, instead of merely asking the build
system to ignore them) ... it's probably still booting the old kernel.
</BLOCKQUOTE>
<BLOCKQUOTE>
Type 'uname -a' to see your running kernel version.
</BLOCKQUOTE>
<BLOCKQUOTE>
When you build your kernel, go into the Makefile at the top of your
sources, and add a marker of your own into the EXTRAVERSION variable.
That way, if you succeed at grafting your own kernel in, then you will
see your marker from the uname output. Also its modules will be
seperated by the extended version, so you won't chance loading the
mouse support module of a kindred kernel, at least not unless you
deliberately insmod it.
</BLOCKQUOTE>
<BLOCKQUOTE>
I do this all the time to mention a systemname when I build kernels that
are only supposed to run on a specific host. Usually it's a warning
that the kernel is unlikely to boot other boxen; sometimes it's a sign
that I succeeded at applying a particular patch, or have a particular
list of options selected.
</BLOCKQUOTE>
<BLOCKQUOTE>
Then type '<tt>make menuconfig</tt>' (not just 'menuconfig') and tweak whatever
things you want or not. Note that X will be useless without some
serious tweaking, e.g. maybe using a windowmanager like ratpoison which
is keyboard driven, and adjusting the config so it won't die without a
mouse.
</BLOCKQUOTE>
<BLOCKQUOTE>
It may be easier to simply adjust the sysvinit setup so it does not
automatically launch gpm for you. You could directly remove the gpm
package so it will stop haunting you (try as root, either '<tt>rpm -e gpm</tt>'
or '<tt>apt-get --purge remove gpm</tt>')... or modify your init sequence so
that gpm is no longer automatically invoked. Note that most distros
also have helper apps to set all the right things for that too - debian
has update-rc.d, <A HREF="http://www.suse.com/">SuSE</A> has YaST, <A HREF="http://www.redhat.com/">Red Hat</A> had linuxconf and may have newer
and more friendly interfaces now, etc. The ultimate arbiter of what
happens during your startup though, is <TT>/etc/inittab</TT>, which is really the
file that init reads when it gets started. All the other stuff is just
following its instructions through a few layers of shell scripts.
</BLOCKQUOTE>
<!-- end 21 -->
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<P> <A NAME="tips.22"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">root like permissions</FONT></H3>
Fri, 11 Apr 2003 21:27:44 -0600
<BR>Jason Creighton (<a href="mailto:linux-questions-only@ssc.com?cc=Chris.Love@ktd-kyocera.com&cc=androflux@softhome.net&subject=%20Re%3A%20%5BLG%2090%5D%202c%20Tips%20%2322">androflux from softhome.net</a>)
<BR>Question by Chris Love (Chris.Love from ktd-kyocera.com)
<P><STRONG>
I am setting up a few Linux machines for the development group and I don't
want them to have root access, but they need to be able to install packages
and whatnot. Is there a way to do this? I tried logging them in as root
and the 1st thing they did was change root password - so that idea no good.
Is there a way to make them a root clone but not able to mess with roots
password and other such files? Similar to a Windows Power User?
</STRONG></P>
<BLOCKQUOTE>
[David Mandala]
What you are looking for is the sudo command. You can let specific users
do specific things that (a limited subset) root can do. This can be by
person or groups of persons.
</BLOCKQUOTE>
<BLOCKQUOTE><BLOCKQUOTE><CODE>
man sudo.
</CODE></BLOCKQUOTE></BLOCKQUOTE>
<BLOCKQUOTE>
[Jason Creighton]
Well......this is a tricky question, because if you set up 'sudo' to let them
use 'rpm', they'll just write a clever RPM that does Bad Things(tm). So, what
you <EM>could</EM> do is something like this:
</BLOCKQUOTE>
<blockQuote><ul>
<LI>Tell them to install software in their home directories. Compile the
software from source, setting the --prefix option to point to somewhere that
user can write to. Then have them adjust PATH and whatnot to point to include
the right directories.
<LI>Use User Mode Linux. (<A HREF="http://user-mode-linux.sourceforge.net"
>http://user-mode-linux.sourceforge.net</A>) This would
set up a virtual linux machine that they could be "root" in, but wouldn't
affect the rest of the machine.
</ul></blockQuote>
<blockquote><font color="#000066">With a particularlty tricksy mind, it's possible to set up a sudo to
make people only have access to a command when they are using the right
parameters. It could get ugly pretty quick though. I like the user
mode linux plan. If you've got some developers working on the same
project, you might even lock them into the same virtual machine, and let
them share full ownership inside it. You will want to keep an eye on
the machines for unusual behavior - defensively and in everyone's best
interests, of course.
-- Heather</font></blockquote>
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<P> <A NAME="tips.23"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">UPS Problems..</FONT></H3>
Wed, 23 Apr 2003 08:05:51 -0700
<BR>Dan Wilder (<a href="mailto:linux-questions-only@ssc.com?cc=smiley0@myrealbox.com&cc=dan@ssc.com&subject=%20Re%3A%20%5BLG%2090%5D%202c%20Tips%20%2323">SSC sysadmin</a>)
<BR>Question by Smiley (smiley0 from myrealbox.com)
<P><STRONG>
I recently got an APC SmartUPS700 for my debian server from a friend. I installed it (although without the serial connection, so the server really shouldn't know that it's there) and an hour or two later my server did something strange - it rebooted itself abruptly, on its own accord. I naturally figured this was something to do with the UPS and since it was late at night and i didn't feel like troubleshooting at the time, i took the UPS out of the picture altogether, and rebooted my server, plugged straight into the mains.
</STRONG></P>
<P><STRONG>
Same thing happened.
</STRONG></P>
<P><STRONG>
This has never happened before and I can't figure out why it's happening. At first i thought it must be a hardware problem, perhaps the UPS has somehow damaged the power supply of the server or something like that - but when I booted it into windows and left it for a few hours nothing happened. It only ever happens in linux.
</STRONG></P>
<P><STRONG>
I really don't know what to do to fix the problem, and it's really getting
to me - i can't listen to any music, surf the web, do email (i'm rushing
to get this written before the computer reboots - the time seems random,
anything from 5 minutes uptime to 3 hours..) or anything else..
</STRONG></P>
<BLOCKQUOTE>
[Dan Wilder]
Very likely hardware. Not likely anything the UPS did.
</BLOCKQUOTE>
<BLOCKQUOTE>
First thing to do is check memory. I recommend memtest86,
</BLOCKQUOTE>
<BLOCKQUOTE>
<A HREF="http://www.memtest86.com"
>http://www.memtest86.com</A>
</BLOCKQUOTE>
<BLOCKQUOTE>
If it finds problems, you certainly have a problem. If it doesn't
it still doesn't mean all is well with hardware or even memory.
Let it run at least four complete passes.
</BLOCKQUOTE>
<BLOCKQUOTE>
Also make sure your processor cooling fan is working and there's
no excessive dust buildup on the processor heat sink or the motherboard
chipset heat sink, if any.
</BLOCKQUOTE>
<BLOCKQUOTE>
[Ben]
I'll strongly ditto that one. Wind0ws doesn't "work" the memory as hard
as Linux does, particularly if you do something like compiling a kernel.
Wind0ws also treats a number of core errors as warnings - viz. the GPFs
and the BSODs ("Blue Screen of Death") - whereas Linux will dump core on
pretty much <EM>any</EM> core error. That policy has lead to a kernel that is
as bug-free as possible, and the process still goes on.
</BLOCKQUOTE>
<BLOCKQUOTE>
[Ken Dodge]
I agree with Dan. I ran across a similar problem with a Win2K box I had
built for my daughter (EPoX EP-8KHA, 1.4GH Athlon) that would
continually reset, sometimes even before completing a boot cycle. She,
too, couldn't depend on it to get anything done. I eventually found a
flakey DIMM, using memtest86. All has been fine since pulling it out
(well ... it IS still running Win2K, but that's another problem!)
</BLOCKQUOTE>
<BLOCKQUOTE>
[Jason Creighton]
Yep. I had a problem once with a box crashing that looked like bad memory.
Turned out that I had EDO turned on in the BIOS but I didn't had EDO RAM in
the box. But in most cases it's bad memory. If you're really hard up for
memory, (Just buying more memory would be much easier) you might want to patch
your kernel to support "BadRAM". You can tell the kernel to not use certain
parts of memory. Here's the URL for that:
</BLOCKQUOTE>
<BLOCKQUOTE><BLOCKQuote>
<A HREF="http://rick.vanrein.org/linux/badram"
>http://rick.vanrein.org/linux/badram</A>
</BLOCKQuote></BLOCKQUOTE>
<BLOCKQUOTE>
memtest86 has an option to output patterns that BadRAM can understand.
</BLOCKQUOTE>
<BLOCKQUOTE>
[Dan WIlder]
Also make sure your processor cooling fan is working and there's
no excessive dust buildup on the processor heat sink or the motherboard
chipset heat sink, if any.
</BLOCKQUOTE>
<BLOCKQUOTE>
[Ben Okopnik]
Or in the power supply vents. Make sure that your power supply fan is
running, too - I've seen that cause more reboots than I could count.
</BLOCKQUOTE>
<!-- end 23 -->
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<P> <A NAME="tips.24"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">To find out what's in an RPM</FONT></H3>
Fri, 4 Apr 2003 11:17:33 -0600
<BR>Gary Sears (<a href="mailto:linux-questions-only@ssc.com?cc=gsears@kane.k12.il.us&subject=%20Re%3A%20%5BLG%2090%5D%202c%20Tips%20%2324">gsears from kane.k12.il.us</a>)
<P>
<a href="../issue89/lg_mail.html#wanted.5">(see question in mailbag, Gazette 4/2003)</a>
</P>
<P>
To emulate rpm's query on a .rpm file, just use gnu's less on it.
Simple. Nice filter.
It shows you the info, patches and files.
</P>
<P>
Since the source for less is available, it might give him a direction...
</P>
<P>
Gary Sears
</P>
<BLOCKQUOTE>
[Jason Creighton]
less doesn't do this. Look at the program named in the LESSOPEN enviromental
varible. On most distos, it's a script that calls diffent programs depending
on the filename. For example, if it's tag.gz or .tgz
</BLOCKQUOTE>
<blockquote><pre>tar -tzvvf filename.tgz
</pre></blockquote>
<BLOCKQUOTE>
to view the contents of a tarball. Or, on my system,
</BLOCKQUOTE>
<blockquote><pre>rpm -qpvl filename.rpm
</pre></blockquote>
<BLOCKQUOTE>
if it's an RPM.
</BLOCKQUOTE>
<P><STRONG>
[John Karns]
Very cool. I had wondered how less was able to handle gzipped text files.
Didn't know it (via $LESSOPEN=lesspipe.sh ... at least on <A HREF="http://www.suse.com/">SuSE</A> 7.x) was
config'd to handle rpm and some others as well.
</STRONG></P>
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<h5>This page edited and maintained by the Editors of <I>Linux Gazette</I><br>HTML script maintained by <A HREF="mailto:star@starshine.org">Heather Stern</a> of Starshine Technical Services, <A HREF="http://www.starshine.org/">http://www.starshine.org/</A>
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