Nagios Installation 4.4.2 (updated 23 Nov 2018)

Nagios installation

Install Ubuntu with LAMP & postfix & Build essentials.

sudo apt-get install build-essential libgd2-xpm-dev apache2-utils unzip

Nagios User Setup

useradd -m -s /bin/bash nagios
passwd nagios
usermod -G nagios nagios
groupadd nagcmd
usermod -a -G nagcmd nagios

Download And Unzip Nagios And Nagios Plugins

mkdir downloads
cd /downloads
wget https://assets.nagios.com/downloads/nagioscore/releases/nagios-4.4.2.tar.gz
wget https://nagios-plugins.org/download/nagios-plugins-2.2.1.tar.gz
tar -zxf nagios-4.4.2.tar.gz
tar -zxf nagios-plugins-2.2.1.tar.gz

Install Nagios

cd /downloads/nagios-4.4.2
./configure --with-command-group=nagcmd
make all
make install
make install-init
make install-config
make install-commandmode
make install-webconf

make install-classicui

Nagios Password

This is the password you will need to look at the nagios pages. If you install Nagios to a different directory please change this command to where the Nagios etc. folder will be.


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

Enter your password when prompted.  Phoenix0
Now we will restart Apache to make sure all of the changes take effect:


/etc/init.d/apache2 restart

Nagios Plugins

cd /downloads/nagios-plugins-2.2.1.tar.gz/


make all
make install

make install-init

make install-commandmode

Now we need to make Nagios start at bootup:

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

Change Default Email Address For Nagios Admin

Open your favorite editor and open /usr/local/nagios/etc/objects/contacts.cfg . (change to J's email)

Once you have saved your changes to the contacts.cfg we need to verify that there are no errors in the configuration of Nagios.


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

Now we are going to start nagios:

service nagios start
/etc/init.d/nagios start

Postfix Configuration For A Smarthost Relay

postconf -e 'relayhost=yourmailserver.com'

postconf -e 'smtp_sasl_auth_enabled = yes'

postconf -e 'smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd'


postconf -e 'smtp_sasl_security_options ='


echo "mail.gmail.com emailusername:scanning@xxxxx.org:Password84" > /etc/postfix/sasl_passwd

Now we will need to change the password file attributes so only root has access to read it.


chown root:root /etc/postfix/sasl_passwd


chmod 600 /etc/postfix/sasl_passwd


postmap /etc/postfix/sasl_passwd





Now we are going to set the map that will change your outbound messages from nagios to your email server username/email address.


echo "nagios scanning@xxxxxx.org" /etc/postfix/canonical


echo "canonical_maps = hash:/etc/postfix/canonical" >> /etc/postfix/main.cf


postmap /etc/postfix/canonical (failed)


/etc/init.d/postfix restart

Now that this all has been completed you can restart your system.
Once your system has come back up you will be able to login to the website and look at your first Nagios installation.


http://yourserver/nagios/


Changing nagios startup screen to tactical view

cd /usr/local/nagios/share
vi index.php
<replace line 2:
  $url = 'main.php';
with
  $url = '/nagios/cgi-bin/tac.cgi';
<save file>

Adding an IP range

hen, Edit file /etc/apache2/sites-enabled/nagios.conf,

sudo nano /etc/apache2/sites-enabled/nagios.conf

And edit the following lines if you want to access nagios administrative console from a particular IP series.

Here, I want to allow nagios administrative access from 192.168.1.0/24 series only. So, I edited this file as shown below.

[...]
## Comment the following lines ##
#   Order allow,deny
#   Allow from all

## Uncomment and Change lines as shown below ##
Order deny,allow
Deny from all
Allow from 127.0.0.1 192.168.1.0/24
[...]

source: http://www.howtoforge.com/nagios-installation-on-ubuntu-10.04-lucid-lynx-p3

source: https://support.nagios.com/forum/viewtopic.php?f=7&t=29198
source: https://www.unixmen.com/how-to-install-nagios-core-4-1-1-in-ubuntu-15-10/