Best of Technical Support

Various

Issue #83, March 2001

Our experts answer your technical questions.

Configuring the Mouse Wheel, Three Ways

I'm wondering if it is possible to config the scrollable mouse to work in Linux like it works in Windows. The mouse I'm using is the Microsoft optical intellimouse. —Ray, wrathstocks@ragingbull.com

Sure! Using the imwheel command you will be able to do it. imwheel -? will tell you the correct syntax. For more information, see jcatki.dhs.org/imwheel.

—Paulo Wollny, paulo@wollny.com.br

Yes. You will find all the information you need at http://www-sop.inria.fr/koala/colas/mouse-wheel-scroll/.

—Marc Merlin, marc_bts@valinux.com

You can set this up in your /etc/X11/XF86Config file. Edit the Pointer section so that protocol is “imps/2”. Below that add these lines:

Option   "Emulate3Buttons"   "off"
Option   "ZAxisMapping"   "4 5"

Then restart X and it should work.

—Paul Christensen, pchristensen@penguincomputing.com

termcap for Connecting to SCO

We have a FoxPro 2.6 for UNIX running in SCO Open Server Release 5. The users access this application from Windows using Tiny Term. We want to move these users to Linux, so far we tried Telnet, defining TERM as scoansi and several other terminals and rlogin with xterm, but we cannot get the right key mappings.

—Jorge C. Oneto, jconeto@jco.wamani.apc.org

According to SCO, many Linux distributions contain incorrect scoansi termcap entries. I believe SCO would be willing to send you a new termcap entry that will fix the problems you are seeing. (Without more details than “cannot get the right key mappings” it's hard to say what exactly is wrong.)

—David Brown, david@caldera.com

I did a migration of a FoxPro application from SCO UNIX to Linux and we had to manually modify a terminfo entry to get a 100% scoansi compatible terminal emulation. After modifying the most adequate (probably vt100 or ansi) terminfo file you will need to compile it using the tic terminfo compiler. Do a man tic to get more information about this command. I would suggest that you look at an actual scoansi emulation definition file on a real SCO system and take a close look at the escape sequences definition so you can port them to Linux (beware of copyright issues if you plan on just copying this file from the SCO system to the Linux system). Another good approach that helped me with the keyboard part is the xmodmap command that lets you define sequences for each key to be sent from the keyboard to the host on an X terminal session.

—Felipe E. Barousse Boué, fbarousse@piensa.com

Bad Password, Bad, Bad!

What controls the composition of a password? How does the system enforce rules on length and mandatory use of non-alphanumeric characters.

—Westley L. Hespeth, hespethw@all-speth.com

For most Linux installations, it is a package called cracklib. PAM (plugable authentication module) uses cracklib to check the validity of a password by using cracklib (usually a special pam_cracklib.so or the like).

—David Brown, david@caldera.com

Unauthorized Hosts Trying to FTP

I am connected to the Internet with a static address. I have been seeing unauthorized FTP access to my system. Even though I have hosts.deny set to ALL:ALL.

The other thing I see is constant probes to tcpd port 1994 from user unknown. These connects look like this:

Nov 21 11:58:10 ns1 tcpd[1994]: warning:


Nov 21 11:58:10 ns1 tcpd[1994]: connect from unknown
Nov 21 11:58:10 ns1 tcpd[1994]: warning:


Nov 21 11:58:10 ns1 tcpd[1994]: connect from unknown

Any advice on plugging these holes?

—Dave Price, davep@support-one.com

It looks like tcpd is simply logging rejected connection attempts. In other words, your hosts.deny is doing its job. A much better and more flexible way to secure a machine is with ipchains. If you're interested check out the ipchains HOWTO at linuxdoc.org.

—Paul Christensen, pchristensen@penguincomputing.com

Using Second CD-ROM Drive in KDE

I installed the Caldera's distribution desktop 2.4 in my computer as a second OS. It's working fine.

I installed a second CD-ROM reader (ATAPI). The new reader and the ancient appears in Windows 98. But in Linux I found only the first CD-ROM. What do I have to do to declare my second CD-ROM? Is it possible to do it with KDE?

—Abderrahmane Meskine, ameskine@finances.gov.ma

You'll need to know where the CD-ROM is attached. After booting, log in as root and run:

dmesg | egrep 'hda|hdb|hdc|hdd'

(assuming it is an IDE device). Then look for your CD-ROM drive(s) in the output. Once you know the device to which your CD-ROM is attached, you can create a new device icon on the KDE desktop that points to your CD-ROM. Rightclick on your current CD-ROM icon and see what the settings are there. Then make a new device icon that is identical to the first in all settings except the actual device string. Change the device string to match what you found from the dmesg... command above (which will be something like

—David Brown, david@caldera.com

Cron Job without Mail from cron

I have a crontab running every ten minutes that does a two-packet ping to keep my network connection alive (why? it's a long story).

The problem I'm faced with is the number of e-mail notifications telling me that the command ran successfully. Is there a way to turn that feature off so that I'm not notified? This generates 144 e-mails/day.

—Scott A. Morrison Markham, scottm@ca.ibm.com

Sure, use this in your /etc/crontab instead.

ping -c 1 target &>/dev/null

—Marc Merlin, marc_bts@valinux.com

Telnet Doesn't Work? Good.

Hi, I am using Mandrake 7.1. After the installation I am unable to Telnet or FTP to my local machine.

telnet localhost<
  telnet:Error message—unable to connect to
         remote host: connection refused

—Pierre, pierre_poo@hotmail.com

Teaching people how to set up Telnet or ftp servers is irresponsible, so we won't do it. Shred your dusty old no-sense-of-security Internet books that explain these two insecure protocols (don't give them to a library; a kid might see them) and install ssh. Most distributions have easy-to-install ssh packages now. If you need to log in to your Linux box from non-Linux clients, check Rick Moen's canonical list of ssh software at: linuxmafia.com/pub/linux/security/ssh-clients.

—Don Marti, info@linuxjournal.com

Need SMP kernel

Do you know if there is a kernel available that supports multiple CPUs? I am using a dual PII 300 but only one of the CPUs is recognized.

—Crist Besore, cbesore@kuhncom.net

You should configure the kernel to enable SMP support:

cd /usr/src/linux
make menuconfig

Select “Processor type and feature” then select “Symmetric multi-processor support”.

—Pierre Ficheux, pficheux@wanadoo.fr

Configuring a Sound Card

I have read all of the README, FAQ and HOW_TO references on configuring a sound card but still am confused as to whether this is a necessity that requires rebuilding the kernel (which I have never done and am a bit nervous about). I detect a SB 3.01 card when I boot but then get an error message about the card being several years old or needing to be reconfigured. Would it be easier for me to go out and purchase a Linux-friendly card?

—Greg McNichol, gc@mcnichol.net

That depends on your card. If it's an ISA-based sound card, it is probably not going to work well unless it's one of the more popular cards, such as a SoundBlaster (NOT a SoundBlaster-compatible). But if it's PCI, you shouldn't be getting that message. In general, most PCI devices should be expected to work with Linux at this point. There are rare exceptions, but they are usually in the area of SCSI and network cards. One thing you should make sure is that there isn't another driver made specifically for your card, because the first driver that THINKS it knows what it's doing is allowed to control a device. This may be bad if your card isn't actually a SoundBlaster or clone, but the driver thinks it is. You can do this by rebuilding your kernel and looking through the sound card options, seeing if any matches it.

—Chad R. Robinson, crobinson@rfgonline.com

Linux on IBM A20p?

I'm a laptop user with an IBM A20p. I can't seem to find any documentation on the Web about installing Linux on my notebook. I hope you can provide me with some aid. Most importantly, I would like to know about the problems I will be facing, like hardware, config, etc. Any help in any form will be greatly appreciated.

—Mikael Koh, dragulako@yahoo.com

There is an install page for your laptop here: www.zhlive.ch/zhl_contents_linux.html

—Marc Merlin, marc_bts@valinux.com

This laptop has been certified by LinuxCare to run well with SuSE 6.4. You can find more information at: www.linuxcare.com/labs/certs/pada20p-suse64-sys.epl and www.zhlive.ch/zhl_contents_linux.html.

—Paul Christensen, pchristensen@penguincomputing.com

PPP Yes, Mail No

When adding a new user, e-mail is automatically granted. What I would like to do is specify a group that when a new user is added, e-mail is not given. An alternative would be removing a user's ability to send or receive e-mail—which I also am unable to find information on. Truly, I'm looking for a PPP.only account.

—Len Elyea, lelyea@ncmc.cc.mi.us

That's a bit hard to do right actually. For incoming e-mail you can alias the accounts to a dummy nonexistent account called nomail. For outgoing, I can't find any good solutions. If you were using exim instead of sendmail, you could have a list of PPP users in a file, and do header rewriting so that the From: and To: headers are rewritten to a nonexistent user, and then enable sender verification (X rewriting rule) to prevent nonexistent users to send mail. That said, this doesn't prevent someone from sending mail by connecting to a remote open relay.

—Marc Merlin, marc_bts@valinux.com

Slow Terminals

When I use any of my terminal emulation programs (GNOME, KDE) the response time is super slow, so slow it makes it very hard to work on the machine. Everything was working fine until yesterday. Could it be something with the display setup? I just can't seem to figure it out. All of the GUI programs work normalllyy. Help!

—Todd Ann Carter, tcarter@healthnetworkamerica.com

If the slow response time issue is at the login time, you may have a host name resolution problem. Try setting the /etc/hosts file with an entry with the IP address and fully qualified domain name of your machine and the line order hosts, bind in the /etc/host.conf file or, correctly setup DNS resolution. On the other hand, have you tried logging it at the console with NO graphics environment? If you can get into the system, try issuing a “ps ax” command to find out which process is taking up so much resources and take corrective actions from there.

—Felipe E. Barousse Boué, fbarousse@piensa.com

Installing Netscape 6 on Red Hat

I'm very new to Linux. I need to install Netscape 6 browser on my Red Had 7.0 box. I did unzip file, downloaded from Netscape and put them under /usr/My_Downloads/netscape 6. What should I do next? I tried double clicking on Netscape-installer, but this does not work. What command should I use to install Netscape 6? Please help.

—Alex, aqk13@hotmail.com

After you've downloaded and unpacked the Netscape 6 tar file, cd into the netscape-installer directory and type

./netscape-installer

An installation wizard should appear giving you options of what to install and where the installation is going to be placed on your system. Make sure to do this as root.

—Paul Christensen, pchristensen@penguincomputing.com