Linux simple fax printer/server mini-HOWTO

2. Questions & Answers

2.1 What is a fax printer server ?

A fax printer server is a setup of few programs: efax, and the print server, in such a way that sending a fax from the computer is as simple as sending printout to a printer.

2.2 How to set it up ?

Setting efax as fax print server includes few problems As I worked it out few times, I decided to collect this wisdom in this small mini-HOWTO, comments are welcome at <erez at newplaces.com>. I describe them here and the solutions, and all the instruction in short steps:

The efax Software

make sure you have the efax package.

On RPM based system use the command 'rpm -qv efax'.

You can get the efax sources in tar.gz format from sunsite: ftp://sunsite.unc.edu/pub/Linux/apps/serialcomm/fax/efax08a.tar.gz or binary rpm package: ftp://ftp.redhat.com/pub/redhat/redhat-4.2/i386/RedHat/RPMS/efax-0.8a-3.i386.rpm

The printcap entry.

The efax documentation is missing the : at the end of the printcap entry.

Solution: Add the following /etc/printcap entry:

fax:\
        :lp=/dev/null:\
        :sd=/var/spool/fax:\
        :if=/usr/bin/faxlpr:

The fax command

Use hard link and not symbolic link to the fax command.

Run the command:

ln /usr/bin/fax /usr/bin/faxlpr

The /usr/bin/fax file.

Edit the /usr/bin/fax to your preferences:

choose the right Fax Class for your modem:

CLASS=2.0

NAME="Your Name"

TELCVT='sed -e s/+972/0/ -e s/+/00/'  # Israel

There is a problem in the file in line 586, change the cfile=... with the following two lines:

cfile=`/usr/bin/tail -1 lock`
cfile=`cat $cfile`

at lines 586,587 there shouldn't be '-' signs the lines are:

0) echo "$l" | mail -s "fax to $num succeeded" $user at $host ;;
*) echo "$l" | mail -s "fax to $num failed   " $user at $host ;;

The /var/spool/fax directory.

create the directory /var/spool/fax

mkdir /var/spool/fax
chmod 777 /var/spool/fax

The lock file.

The lock file (/var/spool/fax/lock) is being created with incorrect permissions, use the following command to set it correctly:

touch /var/spool/fax/lock ; chmod 644 /var/spool/fax/lock

The /dev/modem special file.

The efax program is expecting real device file at the /dev/modem and will not work with symbolic link, so create a device file with the same major and minor number as the /dev/cua? the is connected to the modem. The file should have the rw-rw-rw- mode to enable any user to use the fax software.

ls -lL /dev/modem 
rm /dev/modem
mknod /dev/modem c Mj Mi
chmod 666 /dev/modem

Mj is 5, and Mi is 64 for the cua0, 65 for cua1 and so on. For example (for cua1):

mknod /dev/modem c 5 65

The /var/lock directory.

change the mode at the /var/lock directory

chmod 1777 /var/lock

2.3 How do I use it, for the server ?

You should use the fax printer using the -P option and the -J option with the fax number.

use one of the following lpr commands:

 lpr -Pfax -J <Fax-Number> [file-names]
 any command | lpr -Pfax -J <Fax-Number>

2.4 Where do I specify the target Fax number ?

After the -J option.

2.5 How do I use it from other Unixes on the net ?

Add the following entry into the /etc/printcap file and the client Linux systems, create the spool directory, and so on ...

fax:\
        :sd=/var/spool/fax:\
        :mx#0:\
        :sh:\
        :rm=host.domain:\
        :rp=fax:

add the name of the client hosts into the /etc/hosts.lpd on the fax server machine.

use it as before.

Note:

The header string that efax adds to the fax pages is not effected by the user name that sends the fax. (can be updated).

2.6 Caldera, LPRng users

The LPRng printing management software is using a different method to handle the control file.

Thanks to Luca Montecchiani <m.luca at usa.net>, who found the problem and the solution. Here is an update to the /usr/bin/fax file. The following line replace the two simple cfile=... lines at lines 586,587

# Modified to work also with the LPRng package
# Luca Montecchiani (08/11/97 m.luca at usa.net)
if [ !-z "$CONTROL_FILE" ]
    then
        cfile=`cat tail -1 lock`
        cfile=`cat $cfile`
    else
        cfile=$CONTROL_FILE
fi