If you have ever been to www.kernel.org (which most self respecting Linux person should) then you probably would have notice the bandwidth utilization bar they have, it tells how much bandwidth the server is currently using. You can actually download this program (its a simple one written in C) and put it on your own webserver.

To download the ubar simply go to the following address: http://www.kernel.org/pub/software/web/bwbar/ and download the latest version (currently bwbar-1.2.tar.gz).

All you need to install this program is extract the files from that tarball by typing tar xzvf bwbar-1.2.tar.gz, then cd bwbar-1.2/. Once your in the new directory then simply type make. Now you will have to set it up so that the program runs at startup, this can be done by editing your startup scripts and adding the following to it:

# BwBar / Ubar
echo "Starting Bandwidth Utilization Bar ...";
cd /home/httpd/html/ubar
./bwbar -i -o -t 15 eth0 1.5 &

Now all that is left to do is to setup your some modifications on your site to display this information, firstly create the ./ubar/ directory as in the above script (you may need to change this based on your html directory) and then copy the bwbar program to it by typing cp bwbar /home/httpd/html/ubar/. Once the file has been copied over edit the html file you wish to include the information and place the following lines of html code into it:

<center>
<font size="-1">
<!--#include virtual="ubar/ubar.txt"-->
</font>
<br>
<img src="ubar/ubar.png" alt="Bandwidth Utilization Bar" width=602 height=6 border=0>
</center>

Now with any luck you should have a nice bandwidth utilization bar display on your html page that updates every 15 seconds.

Since most people run a Linux box as a server, there tends to be alot of interest in collecting statistics and figures of the bandwidth that is used through the system, this is where data logging and graphing software becomes rather handy, namely MRTG (Multi Router Traffic Grapher).

"The Multi Router Traffic Grapher (MRTG) is a tool to monitor the traffic load on network-links. MRTG generates HTML pages containing graphical images which provide a LIVE visual representation of this traffic. Check http://www.ee.ethz.ch/stats/mrtg/ for an example. MRTG is based on Perl and C and works under UNIX and Windows NT. MRTG is being successfully used on many sites around the net."

In order to install MRTG successfully on your system, you will also need SNMPD (this is where MRTG collects its information from), you should download and install the latest version of SNMPD, for example here we used ucd-snmp-4.2.5-7.72.0.i386.rpm from www.rpmfind.net which is for a Red Hat 7.2 system (used for this installation). To install the latest rpm of SNMPD simply use the upgrade command of the rpm program, e.g. rpm -Uvh ucd-snmp-4.2.5-7.72.0.i386.rpm. Once you have installed SNMPD simply create the configuration file, /etc/snmp/snmpd.conf and make entries as follows (where <username> is the username you wish to use for access to SNMPD information):

com2sec <username>-snmpd    default         <username>-snmpd


group <username>-snmpd  v1         <username>-snmpd
group <username>-snmpd  v2c        <username>-snmpd
group <username>-snmpd  usm        <username>-snmpd

view all    included  .1                               80

access <username>-snmpd  ""      any       noauth    exact  all none  none

After entering the above information save the file the next best thing is to add an entry to your firewall script to deny access to port 161 (the SNMPD port) from any IP Address that is external to your network, that is you only want to allow access by the server and your clients on the network (192.168.0.* machines for example). When you have safely blocked the port then it is time to start SNMPD by typing /usr/sbin/snmpd (or the appropriate location of the daemon on your system).

Now that SNMPD is installed, configured and running it is time to move onto MRTG, you can download the latest source code from the MRTG home page (www.mrtg.org) or directly from the download page: http://people.ee.ethz.ch/~oetiker/webtools/mrtg/pub/. Here we used mrtg-2.9.21.tar.gz from the MRTG site, once you have downloaded the latest file you must extract the source, tar -xzvf mrtg-2.9.21.tar.gz, then once your in the newly created directory (cd mrtg-2.9.21/) you must ./configure MRTG for your system. Once that is done you need to make and then make install (must be logged in as root for this).

When MRTG has finished installing on your system all that is left to do is create a configuration file before you can run it, to create the default configuration is rather simple using the cfgmaker that is provided, simply enter the following (where <username> is the same as used in installing SNMPD and <machine> is either the IP Address or Hostname of the system):

   cfgmaker --global 'WorkDir: /var/www/html/mrtg'  \
            --global 'Options[_]: bits,growright' \
            --output /home/mrtg/cfg/mrtg.cfg    \
             <username>-snmpd@<machine>

If you wish to run MRTG as a daemon (this is advisable, as it will constantly generate information and statistics for you without being run each time), then you will need to edit the configuration file (home/mrtg/cfg/mrtg.cfg) and add RunAsDaemon: Yes to the line above WorkDir.

It is now time to run MRTG (first time will possibly generate errors as no output files or data exists), /usr/local/mrtg-2/bin/mrtg /home/mrtg/cfg/mrtg.cfg will start MRTG using the configuration file that you created, you may also like to generate an index file for the html, this is done by typing: /usr/bin/indexmaker --output=/var/www/html/mrtg/index.html /home/mrtg/cfg/mrtg.cfg.

The only thing that is now left is to customise the look and feel of the output generated, this can be done by manually editing the configuration file, the best way would be to look on the Internet for samples and adapt them to your needs, once you are satisfied with the way MRTG works then you can leave it to do its job and you now have constant information that is up-to-date and easy to read in regards to your bandwidth etc.