Linmodem-Mini-HOWTO

6. Troubleshooting

So you've read through this document, the Modem-HOWTO, and the PPP Howto, are pretty sure that your modem matches one of the drivers available, but it still doesn't work? There are a number of points in the process at which something could break down.

Linux generally maintains records of networking connections which are very useful in troubleshooting problems. Their particular filenames vary with both the Linux distribution and Dial-in software, but the system log files /var/log/messages, /var/log/syslog, etcetera, should provide at least some information.

For both your own trouble shooting and queries for help to a list, it will be useful if you accumulate the information requested below. As root, change to the directory in which the modem install scripts are located, and start a script record as shown below. After this script is terminated with "exit," copy it out of your Linux partition for transmission to the list which may aid you.

(Below, # are explanatory comments.)

# start the recording,
script ModemTest.txt 
# type in as much info on your Modem card as you have
echo winmodem name, manufacturer, designation, and chip if possible
# this gives your current kernel version
uname -r
# this gives information on your serial ports
setserial -agv /dev/ttyS*
# this information on your interrupts (irq)
cat /proc/interrupts
# show the contents of your module installation script (insert script name):
cat ScriptName
# Check if your script is executable:
ls -l ScriptName
# a response is OK if it has "x" such as below:
# -rwxrw-rw-  1 root     root  654 Jan  6  2000 ltinst
# otherwise make it executable with:
chmod o+x ScriptName
# verify with
ls -l ScriptName
# if ScriptName has not been successfully run before under this kernel
# run it with:
./ScriptName
# what is the symbolic link /dev/modem set to:
ls -l /dev/modem
# What is the DeviceName specified in the ScriptName (/dev/ttyS14 or ...?)
echo DeviceName
# what is your modem driver name? Something like DriverName.o
# with the ".o" indicating it is a compiled binary
echo This is my DriverName.o
# if should have been inserted in the Modules Path
# Try to display it there with:
find /lib/modules | grep DriverName
# Is DriverName among the modules installed in the running kernel?
lsmod
# if not try a simple insertion:
insmod ./DriverName.o
# or if it was in the Modules Path, the following will suffice:
insmod DriverName
# check for insertion:
lsmod
# if not inserted, try forcing:
insmod -f ./DriverName
# list your inserted modules again.
lsmod
# If DriverName is NOT listed, 
# their is an incompatibility between modem hardware, driver and kernel.
# Further effort will be of No use.
# If DriverName is listed, let's do a bit more information.
# You may first wish to rerun the configuration utility 
# used to setup dial-in connections for your Linux installation.
# Remember to edit your PassWord from this record later.
# You will probably be queried for the following information 
# which you should have ready:
#Port to be used (/dev/modem or /dev/ttySn),Dial-inNumber, UserName, PassWord. 
# Run your configuration utility.
YourSetUpConf
# To stop recording 
exit

If dialin was not successfull, append to this a record from your log file. As an example, a section of a /var/log/syslog from a Debian Linux system is below.