Category Archives: Linux

Compile freedts 1.00 on EL6

Just a note to myself, maybe you will find this usefull as well.

In order to compile freedts-1.00 you need to have the GCC, unixODBC and unixODBC-devel packages installed.

Next download and un-tar the freedts package.

for some reason the ‘ODBC_INC’ variable isnt set properly in the configure script. This will lead to an ‘sql.h not found’ message when the –with-unixodbc switch is used. the fix for this is:

Locate the sql.h file on your system:
find / -iname sql.h -print

edit the freetds ./configure script and add the variable. Given example is specific for my system. Make sure you alter it accordingly.

Next configure the compiler
./configure –with-tdsver=7.0 –with-unixodbc=/usr/local –includedir=/usr/include

Make the install using in sequence:
make install
make clean


Howto: change the notification subject and allow KB images in GLPI version 0.90.3

For version 1.9.2 review:


GLPI released their new version 0.90.3.
With new each release two questions seem to be very persistent. These questions are:

  1. How can we change the default notification prefix: [GLPI ] in the email  subject.
  2. How do we enable images in the KB articles.

In this article you will be able to read my personal  opinion on the matter and how to change this GLPI behavior.

Why do you want to change the GLPI  notification prefix.

The most obvious reason is to allow your customer to quickly identify your companies tickets. The rule of thumb in modern system view design is enabling users to quickly: ‘scan, select. act’ Changing the subject to something intuitive enables your customers to do so.

Another point of interest is the possibility to daisy-chain multiple installations of GLPI. By configuring the notification subjects and schemes correctly you can daisy chain multiple installations allowing cross organization enterprise environments to be set up. This is impossible when all installations identify themselfs as ‘GLPI [key].’

How to alter the code to support your custom prefix in GLPI 0.90

In order to alter the subject prefix in GLPI 0.90,  firstly you need to configure your prefix in the Administration>Entities>[your entity]>notifications>Prefix for notifications. Changing this configuration field will correctly alter the prefix to that of your liking. No further code-hacks are required or advised.

Why do you want images in your KB.

Well this is -in my humble opinion- an no brainer. One images shows more detail then i can describe in a thousand words. Images also help speed up the resolution process, especially during nightly hours. It also allows the engineer to intuitively compare the version of the actual situation with the situation documented. Is it all positive then? no, there are some downsides to consider as well.

An image doesn’t replace the engineers know-how and sometimes you want to explicitly trigger this knowledge by not showing any images. Updated applications might look different, actually slowing down the resolution process. Another more technical downside is web server storage. All images need to be stored somewhere and might needlessly clutter the support-system. My point of view is that you need to decide whats best for your situation. Sadly GLPI doesnt allow you to choose yet, it forces images to be removed. If you do need image support, please apply the code-hack below.

Be aware, This wont enable image export to pdf.

How to enable images in the KB

First we need to enable the INSERT function that enables us to add images using the TinyMCE editor. In order to do this two changes need to be made.

In the inc/html.class.php file on line:3837 and line:3871 comment out ( // ) the lines that reads _html = _html.replace .. See screenshots for more details.

Optionally you can enable the ‘image’ button by adding image to the ‘theme_advanced_buttons2 : ‘ line. See images underneath for more details.


The next step is to enable the images to be shown. Without this change the HTMLAWED plugin will add a denied tag to the actual images effectivly telling the browser not to show the image. Additionally the resulting HTML code including the denied: tag will be stored in database also disabling this specific image after the next code modification. Enabling the images afterward requires an search and replace statement in the database. (See comments below).

In the file /lib/htmlawed/htmLawed.php on line 47 add ‘;src: data’ to the end of the line.

Make sure you use an screenshot tool that generates an inline HTML image on the clipboard. Greenshot is an free alternative that does this out of the box.


Configure unixODBC for use with PHP and MSSQL on Oracle Linux

This short article describes how to configure unixODBC 2.2.11-10.el5 in conjunction with PHP 5.3.3-26. Many forums out there contain articles that describe the absence of php_mssql drivers in the oracle yum repo. There various reason for that; non in which Oracle has a part. No matter what reason you like best, there is a decent alternative by using unixODBC.

To help all the people out that are just looking for a solution I wrote this article. I wont go into depths, ill just describe the major steps with some hints and tips. Happy reading 🙂

The OS version of my virtual box image:

Linux sandboxpinguin 2.6.18- #1 SMP Mon Mar 29 18:27:00 EDT 2010 x86_64 x86_64 x86_64 GNU/Linux
  1. Make sure you have the latest version of unixODBC installed. If Yum is configured correctly the following command should do the trick.
     yum update unixODBC
  2. Download the freeDTS driver, this is the driver unixODBC will use to connect to mssql. If wget is available on your production environment (remove it) after running the command:

    . Make sure you are in an desired location like your home folder.

  3. Unpack the tar-Gzip ball by running the following command
    tar -xf  ./freetds-stable.tgz
  4. Browse into the unpacked folder and run the configure command
    ./configure --with-tdsver=7.2 --enable-msdblib
  5. If the configure ran without any issues you can link/compile the driver by running the command:

    and then

    make install

    and then

    make clean

    Congratulations, you are now the pride owner of the freeDTS driver 🙂

The next part tend to get a bit fuzzy, feel free to ask questions in the comment and ill try to answer them to the best of my ability.

There are allot of articles available on how to configure the unixODBC DSN correctly. Be adviced: the config is specific for your setup and usually needs to be tweaked. In order to enable you to ill explain the concepts of unixODBC. Ill point out some documentation, commands and stuff. Afterward ill have a short tutorial of the steps i used to configure the odbc connection.

  1. unixODBC is configured properly by using the


  2. unixODBC will write into:

    files and uses input files to do so;

  3. The connection can be tested with osql commands from bash, but! it will use the hidden .odbc.ini file in your profile instead of the /etc/odbc.ini. PHP and odbcinst use the one in /etc/odbc.ini. If the one in your profile works than make sure it is identical to the one located in /etc/ directory. Below how the osql output will look if configured correctly. (charset isnt relevant in this stage)
  4. Documentation on how to use FreeTDS in conjunction with unixODBC can be found here.
  5. Documentation on how to use ODBC can be found here
    (ignore the freetds configuration here and use ad4 to figure the settings out for your setup)

Next ill describe my steps in order to make it work.

Configuring the FreeTDS driver

  1. Create the file /etc/odbcDriver.ini
  2. Insert the following in the file (check the paths)
    Description     = FreeTDS Driver with protocol v5.0
    Driver          = /usr/local/freetds/lib/
  3. Create the file /etc/odbc.ini
  4. Insert the following and tweak this to match your environment
    Description     = FreeTDS Driver with protocol v5.0
    Driver          = /usr/local/freetds/lib/
    Server          = [SERVERIP]
    Port            = [REMOTE_TSQL_PORT]
    ClientCharset   = UTF-8
    TDS_Version     = 7.1
    Database        = [DATABASENAME]
    Trusted_Connection = Yes      # Required with most MSSQL environments.
  5. Register the ODBC driver
     odbcinst -i -d -f /etc/odbcDriver.ini 
  6. Register the data source
     odbcinst -i -s -f /etc/odbc.ini

Finally test your config by using the php odbc functions.

$sql = "select 1 + 5 as outcome";

$conn = odbc_connect("ExampleSource" , "Username", "Password");
$result = odbc_exec($conn, $sql);
$row = odbc_fetch_array($result);
echo $row['outcome'];

Good luck querying 🙂

Oracle Enterprise Linux 6.x networking

Lately I got many questions regarding the network configuration of Oracle Enterprise Linux 6 (Red Hat Enterprise Linux 6).
Enough to write a little article about it.

It seems that some of the network configuration was altered in OEL6. The reason as far as I know is the implementation of the NetworkManager daemon. I don’t know why they are using CamelCase for the daemon name, but mind that. Even though the NetworkManager should make the configuration as painless as possible (at least thats what the manual page said), it seems to actually make the configuration more of a pain for some.

Below I will cover some topics in an effort to get you going and remove the pain 🙂

Configuring eth0 for manual operation

  • Step 1: disable the NetworkManager daemon
    service NetworkManager stop
  • Step 2: remove the NetworkManager from Init (start-up)
    chkconfig --level 2345 NetworkManager off
  • Step 3: open the ifcfg-eth0 config file (alter the suffix ‘eth0’ to match the adapter of your choice)
    vi /etc/sysconfig/network-scripts/ifcfg-eth0
  • Step 4: Alter the following to match your environment…
    HWADDR={Your MAC address here}
    #PREFIX=24    [can be used alternativly to NETMASK=]
  • Step 5: Write/close the configuration file (:wq in vi)
  • Step 6: Restart the network service
    service network restart
  • TIP 0: Obviously match the configuration above to match your home network.
  • TIP 1: NetworkManager is not always present in which case you can obviously skip step 1 – 2.
  • TIP 2: There are reports that is actually more stable then PREFIX=xx notation.
    My advice, use NETMASK= which is also better understood by non networking guys.
  • TIP 3: Not sure about the correct NETWORK, NETMASK, BROADCAST or PREFIX settings, give ipcalc a try:
    ipcalc --netmask {IPADDR}
    ipcalc --prefix {IPADDR} {NETMASK}
    ipcalc --broadcast {IPADDR} {NETMASK}
    ipcalc --network {IPADDR} {NETMASK}

Configuring DNS

DNS always seems to be a bugger and a hard one to understand. Do note that DNS is JUST A IP PHONEBOOK. Nothing fancy there. Also there are various ways of configuring DNS. One way is by adding the DNS configuration in the ifcfg-suffix configuration file with the DNS1=ip.ip.ip.ip DNS2=ip.ip.ip.ip keywords. As an effect, the networking service will update the appropriate configuration files. To be frank, I find this to be confusing and do not like duplicate configurations everywhere in my -has to be clean- environment. My advice is to configure the DNS is the appropriate files directly like this…

  • Step 1: Edit the resolve.conf where DNS is configured.
    vi /etc/resolv.conf
  • Step 2: Add or Alter the following to match your environment
    search mydomain.home
  • Step 3: Test to see if name resolution works
    set debug
  • TIP 1: Linux actually tries to find the ip in the /etc/hosts file first. If you know the hostnamename and FQDN to an certain IP and it can be classified as static. Consider using the hostsfile instead of a centralized DNS. This will boost performance if the name is resolved often. If multiple systems use and depend on a machine reference, use centralized DNS in order to lighten the administrative tasks.
    vi /etc/hosts
  • TIP 2: Experiencing slow log on times or slow application performance? A faulty DNS configuration might just be the cause. A quick way to test this is by temp. disabling DNS all together. This can be done by editing the /etc/nsswitch.conf file.
    vi /etc/nsswitch.conf
    • alter the line
      hosts:     files dns
    • to the line
      hosts: files
    • write the file and test if the performance has improved.
  • The reason for this is that DNS is often used to register user logon or session information based on the visitors IP address. Examples are the ssh daemon, ftp servers, webservers, linux logon, etc.


In some case you want linux to use alternative routes to access certain Linux resources. The way to go in these cases are creating routes. In most cases you want these to be presistant in which case ‘route add –‘ wont suffice. In our example we will create two new routes. On describing a route to a specific host, the other describing the route to a specific network. Alter the example to match your needs.

  • STEP 1: Create a new file called static-routes in the /etc/sysconfig/ directory
    vi /etc/sysconfig/static-routes
  • STEP 2: Add the following, obviously matching your specific needs
    any net gw metric 1
    any host gw metric 1
  • STEP 3: Restart the network service
    service network restart
  • TIP 1: SIOCADDRT: No such process means the designated gateway doesnt exsist on any known interface. (typo?)
  • TIP 2: view the route information usint the route command
  • TIP 3: use the ipcalc –prefix {IPADDR} {NETMASK} command to determin the right /prefix for your environment.
  • TIP 4: In older environments the ifup-routes is used, this shscript still exsists in the /etc/sysconfig/network-scripts/ifup-routes

Locate my mac address

The ifcfg-eth# config allows you to configure the specific mac address to guarantee the IP is bound to the right adapter. In virtualized environments this might save you a lot of trouble in the situation where the virtualized domain is altered. On the other hand it might cause trouble when the staticly configured MAC is migrated in virtual environments. Either case, you might want to know the MAC linux sees belonging to an certain adapter. You can find the MAC address in the following location:

 cat /sys/class/net/eth0/address

Obviously you need to alter eth0 in the path to match the adapter you are looking for. Not sure? The change directory to /sys/class/net and perform a list to see all discovered and registered adapters.

IPTables (Linux firewall)

By default IPtables (which is the linux firewall) is enabled. You can view the running configuration by checking the service status like this.

 service iptables status

You can simply turn the firewall off by modifying and applying steps 1-2 of the first configuring eth0 instruction. This will reduce the security of your linux platform significantly. My advice, add the ports you need for your services and let IPtables protect you. The easiest way is by simply editing the iptables configuration file.

 vi /etc/sysconfig/iptables 

Adding a port is as easy as copy/pasting the always present firewall rule that allowes port 22 (ssh). Copy past it and alter the -p (protocol) -dport (destination port) to match your needs. For example, allowing HTTP/HTTPS.

-A INPUT -m state --state NEW -m tcp -p tcp --dport 80 -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport 443 -j ACCEPT

afterward restart iptables

service iptables restart

TIP: If you are experimenting with IPv6 (then your Instant COOL!), mind that the ipv6 firewall is called ip6tables and the configuration is called the same. The basic iptables doesnt handle ipv6 at all.

TIP: If you are using ipv6 code your IPv4 ip to ease administration. Example:

ipv6: 2001::0192:0168:0010:0001/64
Then route on the nibble of choice.

Additional questions?

Just post it below and maybe ill respond in due time 🙂

Cant wait…

After reading this benchmark:, I was wondering. isn’t it strange that their own benchmark is telling us they beat the good-old-nagios on all elements?

Do not get me wrong, I still believe that Centreon is a wonderful product. But i cant ignore the fact that the Nagios Core / Nagios XI are on the move as well.  And for some reason I get the feeling they are referring to history. Last time I was informed,  Nagios employed a team of developers as well in developing Nagios XI. And next to that, Nagios also enables OS programmers to commit code:

Please dear Centreon, don’t spoil your good name and stick to the facts. You have a great product, no need for bashing. Next to that, don’t use a translate without review in your benchmark documents.

Having that said, what happed to Icinga?

It seams that Icinga is well on their way as well seeing this sheet:

Anyway, any monitoring needs?

It seems a crossroad is nearing in which you are forced to pick a side and stick by it.

And yet somehow, I cant suppress a feeling of sadness about this development.
Goodbye years of scripting, hacking and rewriting happiness, Hello ‘next-next-finish’ world 😉

Any insights?
Please share them with us web reading it-guy folk  :=)

Backup script for GLPI (

If you are using the great GLPI tool, you will notice that the market value of the data inside will increase rapidly. This usually also implicates that it is ‘wise’ to back this data up.

There are many ways to do so using nice plugins, even nicer gui`s and apps. I (headstrong that I am), wanted something very basic and functional, easy to configure, and that will work in an environment that has multiple GLPI installations. Answer to my question: build something for your own.

So i scripted something for Linux that will allow you to backup the entire GLPI tree (where the uploaded files reside), and the sql database.

Because we use a deduped backup storage (datadomain), i dont have to worry about duplicate data. If you need to, then add something to clean the backup store. This script doesn’t account for that 🙂

This is the script:

# Wrote by Chris
# Goal is to easly backup glpi in a multi installation environment.


#Dont change anything after this point, unless you know what you are doing #
#No guarantees, une this script at own risk                                #

# Do some generic stuff here
# Add checks if you like 🙂
MYSQLDUMP=`which mysqldump`;
AWK=`which awk`;
FIND=`which find`;
DATE=`date +%d.%m.%Y`;
LOGTIME=`date +"%d-%m-%Y %H:%m"`;
DBCONFIG=`find $GLPI_DIR -name "config_db.php"`;
DBNAME=`grep "dbdefault" $DBCONFIG | awk -F '=' '{ gsub(/\047/,""); gsub(/\;/,""); gsub(/ /,""); print $2;}'`;

# Start working....
echo -e "$LOGTIME \t## New backup started ##" >> $LOGFILE;
echo -e "$LOGTIME \tpacking: $GLPISIZE.. into $BACKUP_DIR/backup.$DATE.tar.bz2 ..." >> $LOGFILE;
tar -cjPf $BACKUP_DIR/backup.$DATE.tar.bz2 $GLPI_DIR >> $LOGFILE;
echo -e "$LOGTIME \tCreating mysqldump into $BACKUP_DIR/sqldump.$DATE.sql ..." >> $LOGFILE;
mysqldump $DBNAME > $BACKUP_DIR/sqldump.$DATE.sql;
# Go back to original working directory.
echo -e "$LOGTIME \tAll done..." >> $LOGFILE;
echo "all done! ";

exit 0;

If you want to install this script follow the following instructions:

#This is for Oracle Enterprise Linux / RedHat EL distro`s
#Your environment might be slightly different.
cd /opt
mkdir ./scripts
cd scripts
vi ./
#insert the code above into the editor and save the lot using ':wq'
#alter the top of the script to match your environment.
chmod +x ./
#next create a symbolic link to the cron.daily, this might be different in your linux distro (see manual pages on your distro using 'man cron').
ln -s /opt/scripts/ /etc/cron.daily/backup
#monitor the /var/log/backup.log for details

Happy backing up 🙂

(Dont forget to clean the backup dir on a regular basis if you dont have the luxury of an deduping storage) missing in apache 2.2.19? Check This!

Hi there admins,

Today I spend an hour figuring out why the “Order” directive in apache 2.2.19 resulted in errors.

Knowing that “Order” was previously provided by “” i started my quest in figuring out why that module was missing. What did i find?

Mod_access was renamed or recompiled to “”.
as described here…

after adding the module again it worked like a bliss 🙂

Howto compile apache 2.2.x?, heres a hint 🙂

./configure --prefix=/u01/proxy/ #Where to install?\
--enable-ssl=shared \
--enable-proxy=shared \
--enable-proxy-connect=shared \
--enable-proxy-ftp=shared \
--enable-proxy-http=shared \
--enable-proxy-ajp=shared \
--enable-proxy-balancer=shared \
--enable-cache=shared \
--enable-file-cache=shared \
--enable-mem-cache=shared \
--enable-disk-cache=shared \
--enable-deflate=shared \
--enable-http=shared \
--enable-dav=shared \
--enable-vhost-alias=shared \
--enable-rewrite=shared \
--enable-so=shared \
--with-ssl=/usr/bin/openssl > ./reviewlog.txt
make >> ./reviewlog.txt
make install >> ./reviewlog.txt
make clean

Compile PHP5.3.6 on OEL5.5 x64

All you need is apache installed, then download php 5.3.6. src and run the following configuration command.

./configure --build=x86_64-redhat-linux-gnu --prefix=/usr --exec-prefix=/usr --bindir=/usr/bin --sbindir=/usr/sbin --sysconfdir=/etc --datadir=/usr/share --includedir=/usr/include --libdir=/usr/lib64 --libexecdir=/usr/libexec --localstatedir=/var --sharedstatedir=/usr/com --mandir=/usr/share/man --infodir=/usr/share/info --cache-file=../config.cache --with-libdir=lib64 --with-config-file-path=/etc --with-config-file-scan-dir=/etc/php.d --disable-debug --with-pic --disable-rpath --without-pear --with-bz2 --with-curl --with-exec-dir=/usr/bin --with-freetype-dir=/usr --with-png-dir=/usr --enable-gd-native-ttf --without-gdbm --with-gettext --with-gmp --with-iconv --with-jpeg-dir=/usr --with-openssl --with-pcre-regex --with-libexpat-dir=/usr --with-zlib --with-layout=GNU --enable-exif --enable-ftp --enable-magic-quotes --enable-sockets --enable-sysvsem --enable-sysvshm --enable-sysvmsg --enable-wddx --with-unixODBC=shared,/usr --enable-shmop --enable-calendar --with-libxml-dir=/usr --with-apxs2=/usr/sbin/apxs --with-mysql --with-gd --enable-soap --enable-mbstring --with-xsl --disable-dba --without-unixODBC --disable-xmlreader --disable-xmlwriter

Next note the errors during configuration and install the required packages needed from the install media then rerun the command up till it finishes succesfully.

When the configuration is done, run the “make all” command after which you are requested to run the “make test” command. Then finaly run the “make install” command.

Installing the correct packages might consume some time…

Good luck! 🙂

–If you encounter an “Cannot find libmysqlclient” error you either didnt install all the mysql packages or you need to add –with-libdir=lib64 behind the –with-mysql=/usr/bin entry.

(The mysql module isnt shipped anymore with the distribution!)

network issues with Dell Broadcom interfaces?

Experiencing “Copper Link Down” messages with increased network load on Dell R and M Series servers?

Then you might want to look into this thread.

There is a known issue with the bnx2 driver used on the Linux platform that might cause the network card to become inactive. The problem is caused by the drivers MSI (Message Signaled Interface) option.

The two suggested solutions to this problem are;

1. Disable the msi option in the modprobe.conf file by adding the following rule;
options bnx2 disable_msi=1 (Recommended)

2. Load the latest dell driver that disables the msi-x option in the driver itself.

Please read these threads carefully before you decide this problem is the one you might be experiencing.

How to detect the problem on OracleVM / OEL.

1. Make sure the Link-led is lid on the back op the physical machine.
2. Run the ethtool eth# -t to view its current state
3. Make sure the ethtool reports a Link-Down

Applying the fix use the following steps;

1. Logon to the OracleVM Dom0 / OEL / Other Linux box.
2. vi /etc/modprobe.conf
3. Add the following line below alias eth0 bnx2
options bnx2 disable_msi=1
4. Save and quit vi :sq
5. Reinit the module using the following command.
modprobe bnx2
6. Verify the setting using the following command.
modinfo bnx2
The following rule should be listed.
parm: disable_msi:Disable Message Signaled Interrupt (MSI) (int)

Hope this fix resolves the problem for you!


RHEL5 init script for tomcat catalina

I have written an init script for Tomcat Catalina running in RHEL version 5. I have tested this script using Oracle Enterprise Linux 5.5 Carthage. The script should comply to the init standards defined for RedHat Enterprise Linux using the INIT Functions lib.

The script also alows the use of chkconfig eventhough you might want to alter the used priorities (56 10)

# "$Id: catalina ,v 1.0 2010/08/10 Chris_g Exp $"
#   Startup/shutdown script for tomcat(Catalina) Application server.
#   Linux chkconfig stuff:
#   chkconfig: 2345 56 10
#   description: Startup/shutdown script for the tomcat application server.

# Source function library.
. /etc/init.d/functions

# Define where the script is located.
CATALINA_BIN='/u01/tomcat/bin/ 1> /dev/null';

# Find the catalina process using ps / awk.
# The match function will return 0 when no match is found with the string "java".
# Position $9 should contain the path to the Java executable used by catalina.
PROC=`ps -efc | grep apache.catalina | awk 'BEGIN { FS=" "}; { if( match($9, "java") != 0 ) print $9;}'`

# Replace a potential empty string with a fake process so the RH daemon functions are able to parse
# it properly
if [[ "$PROC" == '' ]]; then

# Define the application name that is listed in the daemonize step.
PROG='Tomcat JVM';


start () {
        echo -n $"Starting $PROG: "

        # start daemon
        daemon $CATALINA_BIN start
        [ $RETVAL = 0 ] && touch $LOCK
        return $RETVAL

stop () {
        # stop daemon
        echo -n $"Stopping $PROG: "
        killproc $PROC
        [ $RETVAL = 0 ] && rm -f $LOCK

restart() {

case $1 in
                status $PROC

        echo $"Usage: $prog {start|stop|restart|status}"
        exit 3

exit $RETVAL

1. Touch a new tomcat file in your init directory.
>touch /etc/init.d/tomcat
2. Copy paste the code above into this file using vi
vi /etc/init.d/tomcat
(putty users)
press the insert button (this should put vi in insert mode)
Alter the tomcat path and copy the altered code to your clipboard and paste it into putty using a richt mouse click.
press esc (this should get you out of insert mode)
next press ” shift + : “, “w”, “enter” (this should save the file)
3. If was able to start tomcat (all vars/java configured) then now the tomcat script should be able to handle the startup.
4. If catalina was allready running, try;

     service tomcat status
     This should allready give a result equal to;
     java (pid 14389) is running…

5. Add tomcat to the chkconfig for automatic startup
     chkconfig –level 2345 tomcat on

Hope this helps 😉