How to install nagios server in Ubuntu 16.04 LTS

How to install server in Ubuntu 16.04 LTS. Nagios is one the robust and very good monitoring server which is highly used in corporate network either it is Small business Unit or big corporate.

Step 1: Login into the server and become a superuser root
$ sudo su -
Step 2: Now install Nagios,apache,php
Step 3: while installation you will get below given screen for postfix installation
Select Internet Site and then select OK and do enter.

Step 4: Now as per below given screen give FQDN or hostname of your system. Replace example.com with your domain name else only hostname will also work you can change it later from postfix configuration. Select ok and enter

Step 5: Now in next screen it will ask you to set Nagios Web Administrator password.
Give password and OK then enter

Note: Nagios Web Admin bydefault user name is nagiosadmin

Step 6: Type once again your password and reconfirm. Select OK and enter.
Now after this rest of the procedure will run itself and installation will be finished within a few minutes.

Step 7: Now restart the apache and nagios once. It is not necessary but it is good to check once again.

# /etc/init.d/apache2 restart

# /etc/init.d/nagios3 restart

Step 8 : Now open the browser from other system .
In url type, http://ip-address-of-nagios-server/nagios3

Username : nagiosadmin
Password : Enter your password which you have set for nagiosadmin