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Quickstart Installation Guides install Nagios from source (code) on Ubuntu

27-Nov-09

Quickstart Installation Guides install Nagios from source (code) on Ubuntu

* Nagios and the plugins will be installed underneath /usr/local/nagios
* Nagios will be configured to monitor a few aspects of your local system (CPU load, disk usage, etc.)
* The Nagios web interface will be accessible at http://localhost/nagios/
Required Packages

Make sure you’ve installed the following packages on your Ubuntu installation before continuing.

* Apache 2
* PHP
* GCC compiler and development libraries
* GD development libraries

You can use apt-get to install these packages by running the following commands:

sudo apt-get install apache2

sudo apt-get install libapache2-mod-php5

sudo apt-get install build-essential


With Ubuntu 6.10, install the gd2 library with this command:

sudo apt-get install libgd2-dev

With Ubuntu 7.10, the gd2 library name has changed, so you’ll need to use the following:

sudo apt-get install libgd2-xpm-dev

1) Create Account Information

Become the root user.

sudo -s

Create a new nagios user account and give it a password.

/usr/sbin/useradd -m -s /bin/bash nagios

passwd nagios

On older Ubuntu server editions (6.01 and earlier), you will need to also add a nagios group (it’s not created by default). You should be able to skip this step on desktop, or newer server editions of Ubuntu.

/usr/sbin/groupadd nagios

/usr/sbin/usermod -G nagios nagios

Create a new nagcmd group for allowing external commands to be submitted through the web interface. Add both the nagios user and the apache user to the group.

/usr/sbin/groupadd nagcmd

/usr/sbin/usermod -a -G nagcmd nagios

/usr/sbin/usermod -a -G nagcmd www-data

2) Download Nagios and the Plugins

Create a directory for storing the downloads.

mkdir ~/downloads

cd ~/downloads

Download the source code tarballs of both Nagios and the Nagios plugins (visit http://www.nagios.org/download/ for links to the latest versions). These directions were tested with Nagios 3.1.1 and Nagios Plugins 1.4.11.

wget http://prdownloads.sourceforge.net/sourceforge/nagios/nagios-3.2.0.tar.gz

wget http://prdownloads.sourceforge.net/sourceforge/nagiosplug/nagios-plugins-1.4.11.tar.gz

3) Compile and Install Nagios

Extract the Nagios source code tarball.

cd ~/downloads

tar xzf nagios-3.2.0.tar.gz

cd nagios-3.2.0

Run the Nagios configure script, passing the name of the group you created earlier like so:

./configure --with-command-group=nagcmd

Compile the Nagios source code.

make all

Install binaries, init script, sample config files and set permissions on the external command directory.

make install

make install-init

make install-config

make install-commandmode

Edit the /usr/local/nagios/etc/objects/contacts.cfg config file with your favorite editor and change the email address associated with the nagiosadmin contact definition to the address you’d like to use for receiving alerts.

vi /usr/local/nagios/etc/objects/contacts.cfg

5) Configure the Web Interface

Install the Nagios web config file in the Apache conf.d directory.

make install-webconf

Create a nagiosadmin account for logging into the Nagios web interface. Remember the password you assign to this account – you’ll need it later.

htpasswd -c /usr/local/nagios/etc/htpasswd.users nagiosadmin

Restart Apache to make the new settings take effect.

/etc/init.d/apache2 reload

Note Note: Consider implementing the ehanced CGI security measures described here to ensure that your web authentication credentials are not compromised.

6) Compile and Install the Nagios Plugins

Extract the Nagios plugins source code tarball.

cd ~/downloads

tar xzf nagios-plugins-1.4.11.tar.gz

cd nagios-plugins-1.4.11

Compile and install the plugins.

./configure --with-nagios-user=nagios --with-nagios-group=nagios

make

make install

7) Start Nagios

Configure Nagios to automatically start when the system boots.

ln -s /etc/init.d/nagios /etc/rcS.d/S99nagios

Verify the sample Nagios configuration files.

/usr/local/nagios/bin/nagios -v /usr/local/nagios/etc/nagios.cfg

If there are no errors, start Nagios.

/etc/init.d/nagios start

8) Login to the Web Interface

You should now be able to access the Nagios web interface at the URL below. You’ll be prompted for the username (nagiosadmin) and password you specified earlier.

http://localhost/nagios/

Click on the “Service Detail” navbar link to see details of what’s being monitored on your local machine. It will take a few minutes for Nagios to check all the services associated with your machine, as the checks are spread out over time.

9) Other Modifications

If you want to receive email notifications for Nagios alerts, you need to install the mailx (Postfix) package.

sudo apt-get install mailx

sudo apt-get install postfix

You’ll have to edit the Nagios email notification commands found in /usr/local/nagios/etc/objects/commands.cfg and change any ‘/bin/mail’ references to ‘/usr/bin/mail’. Once you do that you’ll need to restart Nagios to make the configuration changes live.

sudo /etc/init.d/nagios restart

Reference : http://nagios.sourceforge.net/docs/3_0/quickstart-ubuntu.html

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Understanding TCP/IP and Architectural Principles of the Internet

27-Nov-09

To fully understand the architecture of Cisco Centri Firewall, you need to understand the TCP/IP architecture on which the Internet is based. This appendix discusses the TCP/IP architecture and provides a basic reference model that can help you understand how Cisco Centri Firewall operates. It explains TCP/IP terminology and describes the fundamental concepts underlying the TCP/IP protocol suite. We begin by providing a common frame of reference to use as a basis for the rest of the discussion contained in this appendix on TCP/IP and Cisco Centri Firewall.

http://www.cisco.com/univercd/cc/td/doc/product/iaabu/centri4/user/scf4ap1.htm

Architectural Principles of the Internet


ftp://ftp.rfc-editor.org/in-notes/rfc1958.txt

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Download chrome browser development version for ubuntu

25-Nov-09

Download chrom development version for ubuntu

You can download the development verion from the url below, there are versions available for other platform also from the url.

http://ppa.launchpad.net/chromium-daily/ppa/ubuntu/pool/main/c/chromium-browser/

Adding the repository:

https://launchpad.net/~chromium-daily/+archive/ppa

deb http://ppa.launchpad.net/chromium-daily/ppa/ubuntu karmic main
deb-src http://ppa.launchpad.net/chromium-daily/ppa/ubuntu karmic main

deb http://ppa.launchpad.net/chromium-daily/ppa/ubuntu intrepid main
deb-src http://ppa.launchpad.net/chromium-daily/ppa/ubuntu intrepid main

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Adding google repository to Ubuntu or Debian based distros

24-Nov-09

Adding google repository to Ubuntu or Debian based distros.

Add the following rule to e.g. /etc/apt/sources.list, or if your distro has the /etc/apt/sources.list.d/ directory, add it to a file called google.list in that directory:

# Google software repository
deb http://dl.google.com/linux/deb/ stable non-free main

Once the above entry is added we can run apt as usual.

sudo apt-get update
sudo apt-get install picasa

For other distros – check – www.google.com/linuxrepositories/apt.html

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running fsck on reboot

24-Nov-09

The -F option force fsck on reboot, login as root and type the following command to reboot and run fsck:

# shutdown -rF now

-F Force fsck on reboot.
-r Reboot after shutdown.
-k Don’t really shutdown; only send the warning messages to everybody.

or

Login as user root and create a file called forcefsck:

# touch /forcefsck

Now reboot the system:

# reboot

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Running fsck on your server

24-Nov-09

Q. My laptop partition  /dev/sdb1  is showing file system error, how  do i use fsck command to check for file system error and repair the partition.

Solution  is to use   fsck – check and repair a Linux file system or use e2fsck – check a Linux ext2/ext3 file system.

Device              Start       End Blocks      Id                      System
/dev/sdb1      1               2861              2011014+ 6   FAT16

Step 1 – Go to single user mode if needed and then Unmount the partition.

root@laptop:# init 1     [for my laptop there was no need to go to single user mode, as i was able to unmount the partition]

root@laptop:# umount /dev/sdb1

Step 2 – Run Fsck on /dev/sdb1

root@laptop:# fsck -yvf /dev/sdb1

fsck 1.41.4 (27-Jan-2009)
dosfsck 3.0.1 (23 Nov 2008)
dosfsck 3.0.1, 23 Nov 2008, FAT32, LFN
Checking we can access the last sector of the filesystem
Boot sector contents:
System ID “MSDOS5.0″
Media byte 0xf8 (hard disk)
512 bytes per logical sector
32768 bytes per cluster
4 reserved sectors
First FAT starts at byte 2048 (sector 4)
2 FATs, 16 bit entries
125952 bytes per FAT (= 246 sectors)
Root directory starts at byte 253952 (sector 496)
512 root directory entries
Data area starts at byte 270336 (sector 528)
62835 data clusters (2058977280 bytes)
63 sectors/track, 255 heads
243 hidden sectors
4022029 sectors total
Reclaiming unconnected clusters.
/dev/sdb1: 1050 files, 53941/62835 clusters

You can also user logsave which saves the output of a command in a logfile.

root@laptop:# logsave -asv /var/log/fsck.log fsck -y /dev/sdb1
Log of fsck -y /dev/sdb1
Tue Nov 24 13:25:06 2009

fsck 1.41.4 (27-Jan-2009)
dosfsck 3.0.1, 23 Nov 2008, FAT32, LFN
/dev/sdb1: 1050 files, 53941/62835 clusters

Tue Nov 24 13:25:07 2009

Remount after running fsck

root@laptop:# mount /dev/sdb1 /media/home2/

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setuid for programs

23-Nov-09

setuid program are programs, which runs as owner of the program, rather than the user executing the program.

root@laptop:~# ls -l `which su`
-rwsr-xr-x 1 root root 31012 2009-04-04 11:19 /bin/su
root@laptop:~# ls -l `which sudo`
-rwsr-xr-x 1 root root 115136 2009-02-17 08:52 /usr/bin/sudo
root@laptop:~#

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Reconfigure PHP5 on cPanel Server for XSL

23-Nov-09

Requirements

This extension uses libxslt which can be found at » http://xmlsoft.org/XSLT/. libxslt version 1.1.0 or greater is required.

CUSTOM_PHP_FLAGS="--with-xsl" /scripts/easyapache

http://in3.php.net/manual/en/xsl.installation.php

On debian –

sudo apt-get install php5-xsl

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Fail Open DNS Servers

23-Nov-09

Closing open DNS server. Add the following to your named.conf file.

Add the following, replacing mainIP and secondaryIP with your systems nameservers.

acl "trusted" {
mainIP;secondaryIP;127.0.0.1;
};

Example:

acl "trusted" {

mainIP;secondaryIP;firstserverip;secondserverip;127.0.0.1;

};

Only the trusted IP is allowed for certain functions.

allow-recursion { trusted; };
allow-notify { trusted; };
allow-transfer { trusted; };

Example:

include "/etc/rndc.key";

controls {
inet 127.0.0.1 allow { localhost; } keys { "rndckey"; };
};

acl "trusted" {
ip1;ip2;ip3;ip4;ip5;127.0.0.1;
};

//
// named.conf for Red Hat caching-nameserver
//

options {
directory "/var/named";
allow-recursion { trusted };
allow-notify { trusted };
allow-transfer { trusted };
dump-file "/var/named/data/cache_dump.db";
statistics-file "/var/named/data/named_stats.txt";
/*
* If there is a firewall between you and nameservers you want
* to talk to, you might need to uncomment the query-source
* directive below. Previous versions of BIND always asked
* questions using port 53, but BIND 8.1 uses an unprivileged
* port by default.
*/
// query-source address * port 53;

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The Google Chrome Operating System

23-Nov-09

The Google Chrome Operating System

Google Chrome OS is an open source, lightweight operating system that will initially be targeted at netbooks. Google Chrome OS will run on both x86 as well as ARM chips.

Google Chrome OS is an open source operating system created by Google designed to work exclusively with web applications. Announced on July 7, 2009, Google Chrome OS is set to have a publicly available stable release during the second half of 2010

More – at http://chrome.blogspot.com/

http://chrome.blogspot.com/2009/11/announcing-chromium-os-open-source.html

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