How it works:

There are many CA (Certificate Authorities) around the world that they can generate a certificate for you once you provide the required information and identify that you are the owner of the domain or subdomain where you are planning to use the certificate. Most of them are providing this service for an amount money but there are also free solutions. This is something that you need to do if you want to host a service like a web site and you want that everything that is transmitted from any client to your server and vice versa will be encrypted. In the other hand the clients also need to be sure that they can access your server in a secure way. And since they are not able to check your certificate we are relying to a CA to do the job. But if you need to protect an internal website that is running inside your company, then you can become a local CA. Here is how

Became a local CA

issue the following command in order to create a new key that we will use later for our CA certificate.

openssl genrsa -aes256 -out CA.key 4096

You should provide a password twice and the key is ready to use.
The output should look like this:

Generating RSA private key, 4096 bit long modulus (2 primes)
…………………………………………………………………………………..++++
…………………………………………………………………………………………….++++
e is 65537 (0x010001)
Enter pass phrase for CA.key:
Verifying -- Enter pass phrase for CA.key:

Now you have a file that is called CA.key and the contents should be like that:

—--BEGIN RSA PRIVATE KEY—--
Proc-Type: 4,ENCRYPTED
DEK-Info: AES-256-CBC,438387DEFA5FD5275315FD562F1BC0D8

GXs5bW36Ifl0PvP4VYKktVLyxzpHNTkjh+dxMCfQRp9RfKBZl6rjVqYd2hovC01o
DzqIzeVMkT7GWUw3zYUulIYqXDRALTwNa8X5cEF2qtxFQCmMNpK1uHSl761Agtqm
—many lines have been removed—
3vOqEUBD7CNFeS4lkGG4xrsZBdALEFRyPPbzpnIrDwY+jvoLDVSFy7jXncgwFEem
jiUwxpBySCKAP8oMPISlTwh+K9lJ0JgMN1TahCMkdYB8GcTud5+wR8hvl4Wc7gzM
—--END RSA PRIVATE KEY—--

Create a CA Certificate:

Now we need to create a certificate that we are going to install on all systems in our company that they will use the certificates that we are going to create with this CA certificate. So this is a root certificate that a computer is using to identify all certificates that are issued from our CA. Now you need to issue the following command and provide the password from the key we created in the previous step and answer the questions. 

openssl req -x509 -new -nodes -key CA.key -sha512 -days 365 -out CA.pem
Enter pass phrase for CA.key:
You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter ‘.’, the field will be left blank.
—--
Country Name (2 letter code) [AU]:GR
State or Province Name (full name) [Some-State]:-
Locality Name (eg, city) []:Athens
Organization Name (eg, company) [Internet Widgits Pty Ltd]:MyCompanyName
Organizational Unit Name (eg, section) []:IT
Common Name (e.g. server FQDN or YOUR name) []:MyCompanyName.local
Email Address []:info@MyCompanyName.local

Create an SSL certificate using our CA

Now as before we will need to create another key so we can generate a CSR file with all info about our domain and then we will use this file to issue a certificate.

Create the Key:

openssl genrsa -out allaboutlinux.local.key 4096

Create the CSR file:

openssl req -new -key allaboutlinux.local.key -out allaboutlinux.local.csr
You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter ‘.’, the field will be left blank.
—--
Country Name (2 letter code) [AU]:GR
State or Province Name (full name) [Some-State]:-
Locality Name (eg, city) []:Athens
Organization Name (eg, company) [Internet Widgits Pty Ltd]:MyCompanyName
Organizational Unit Name (eg, section) []:IT
Common Name (e.g. server FQDN or YOUR name) []:allaboutlinux.local
Email Address []:info@allaboutlinux.local

Please enter the following ‘extra’ attributes
to be sent with your certificate request
A challenge password []:MySecurePassword!
An optional company name []:

Create the certificate from CSR signed by the CA:

openssl x509 -req -in allaboutlinux.local.csr -CA CA.pem -CAkey CA.key -CAcreateserial -out allaboutlinux.local.crt -days 100 -sha512

Now you can use this certificate on the server side and as long as the clients already have the CA certificate they will be able to identify this certificate and any other that we will create in the future by using the same CA.

install Netbeans in Ubuntu.

Installing required software.

Before we install Netbeans we need to install Apache2 and Php.

sudo apt-get update
sudo apt-get install apache2 php

Now lets install Netbeans

sudo apt-get install netbeans

Now we need to add the php support for Netbeans. go and download that from the official website https://netbeans.org/downloads/index.html

Once the download completes then do to Downloads directory make the file executable and run it.

cd ~/Downloads/
sudo chmod +x netbeans-8.2-php-linux-x64.sh
./netbeans-8.2-php-linux-x64.sh

Then follow the wizard and install it.

This script will update the Netbeans and add php components into the IDE.

before we create a new project we need to add write permissions in the Apache root directory so netbeans will  be able to write directly into this directory.

sudo chmod 777 /var/www/html/

Lets create a new project.

Open Netbeans from Ubuntu Menu and click on "File" and then "New Project"

Select "PHP" --> "PHP Application" and click "Next"

Then change the project name and click next.

On the next window click the check box "copy files from Sources Folder to another location" and add the "html" after "/var/www/"

Now click finish and lets create a small php project where we will try to authenticate a user.

in the index.php just delete everything and copy the following:

<?php
   ob_start();
   session_start();
?>
<html lang = "en">
   
   <head>
      <title>allaboutlinux.eu</title>
      <link href = "css/bootstrap.min.css" rel = "stylesheet">
    
      
   </head>
	
   <body>
      
      <h2>Enter Username and Password</h2> 
      <div class = "container form-signin">
         
         <?php
            $msg = '';
            
            if (isset($_POST['login']) && !empty($_POST['username']) 
               && !empty($_POST['password'])) {
				
               if ($_POST['username'] == 'allaboutlinux.eu' && 
                  $_POST['password'] == 'aal.eu') {
                  $_SESSION['valid'] = true;
                  $_SESSION['timeout'] = time();
                  $_SESSION['username'] = 'allaboutlinux.eu';
                  
                  echo 'You have entered valid use name and password';
                  header("Location: http://localhost/allaboutlinuxeu/correct_password.php");
               }else {
                  $msg = 'Wrong username or password';
               }
            }
         ?>
      </div> <!-- /container -->
      
      <div class = "container">
      
         <form class = "form-signin" role = "form" 
            action = "<?php echo htmlspecialchars($_SERVER['PHP_SELF']); 
            ?>" method = "post">
            <h4 class = "form-signin-heading"><?php echo $msg; ?></h4>
            <input type = "text" class = "form-control" 
               name = "username" placeholder = "username" 
               required autofocus></br>
            <input type = "password" class = "form-control"
               name = "password" placeholder = "password" required>
            <button class = "btn btn-lg btn-primary btn-block" type = "submit" 
               name = "login">Login</button>
         </form>
			
         
         
      </div> 
      
   </body>
</html>

Then lets adds one more php file that will just say "Login succesfull" if you provide the right username and password.

Right click on "Source files" --> "New" --> "PHP File…" and give the filename that we added in the index.php as redirected page. In this case "correct_password.php". Delete everything and paste the following:

<!DOCTYPE html>
<!--
To change this license header, choose License Headers in Project Properties.
To change this template file, choose Tools | Templates
and open the template in the editor.
-->
<html>
    <head>
        <meta charset="UTF-8">
        <title></title>
    </head>
    <body>
        <?php
        // put your code here
        echo("Login succesfull");
        ?>
    </body>
</html>

Now click on "Run" --> "Rub Project" or hit "F6″. If everything was right then you should see a login page and if you give as username "allaboutlinux.eu" and password "aal.eu" you will get redirected into the correct_password page.

Have fun! Create your own pages and post your results here.

iSCSI server with OpenSuse.

In this tutorial i will try to demonstrate how you can create an iSCSI target and then mount it on another machine.

For that i will use the latest available OpenSuse at this time which is the Leap 42.3. I guess that this can be followed by other versions also.

login to OpenSuse, open a terminal and type:

sudo zypper update
sudo zypper install yast2-iscsi-lio-server

Once this is over then you need to open yast and then find and open the "iSCSI LIO Target".

On the first tab "Service" under the section:

"Service start"

Choose if you want the server to run automatically on startup of O.S. or manually.

"Firewall settings for SuSEfirewall2″

click the checkbox "Open port Firewall" if you want to let the system do it for you, otherwise you can also do that manually later on.

After that click on the next tab "Global" and the Discovery credentials. You can let that free by clicking the "No discovery Authentication’ 

On the last tab "Targets" we are going to define the Targets, but before we do so we need to prepare the partition. On this example i use  a secondary disk that it is attached to the computer as raw and has nothing on it. Go to yast again and open "Partitioner". A warning will come up and you can click yes. On the Partitioner click on the left "Hard Disks" and then select the disk that you wanna use. In my case it is the "/dev/sdb". Click on the "Add Partition", select "Primary Partition" and click "Next".  On the next window select "Maximum Size" in order to use the entire disk and then click "Next". If you asked about the role of this partition then select "Operating System" and "Next".

In the last step it is important to select "Do not format partition" and "Do not mount partition" and then click "Finish". 

Ok so now we can go back to "iSCSI LIO Target" and click on the last tab "Targets" and then click "Add". Now most of the textboxes are filled by the system and you can modify them if needed but i will let them to default for now. This should look like the following picture but with different Target name, Identifier, and IP address.

Click in "Add" so we can add our first and only in that case LUN. If you wish to add more just repeat the following process. The LUN number in the following window should be already there and if this is your first LUN then it should be "0″. Now the Path needs to be the path to partition that we created before. In my case it is /dev/sdb1/. you can also add a name but if you let it empty the system will create one for you. Click "OK" and "Next" on the next window.

Now you should be on the following window.

Click the "Add" and provide the Initiator name that are going to connect to that target. Only the initiators with the identical name will be able to connect. We will use this name later on when we will try to connect that from another machine. This name has a specific syntax and it has to be like that:

iqn:yyyy-mm.reversed.domain.name[:identifier]  or something like that: eui:yyyy-mm.reversed.domain.name[:identifier] I ll use the following but you can modify that as you wish "iqn.2017-04.eu.allaboutlinux:my.first.iscsi"

click "OK"

Now you should be able to see the target in the target list ans you can click Finish. The export is created and the server is running!

Mount the target into another computer in the same network.

lets try now to connect this to another computer. I ll use again another OpenSuse computer and after opening yast this time i will select "iSCSI Initiator". The first tab "Service" appears and you can select if that will run automatic on system boot or manually under the "Service Start" section. Then you need to specify the "Initiator Name" that we defined before. 

Now you need to go to the 2nd tab "Connected Targets" and click on "Add". On the upcoming screen you need to type the IP address of the iSCSI target and click next.

Now you should be able to see the target and you have to click on connect.

On the upcoming window under the "Startup" select "automatic" and the initiator will connect to the target automatically when the server is coming up. Click next and you will be able to see that the target is now connected. Click on "Next" and "Finish". Now you you should be able to see the disk under the list of your disks in the "Partitioner". Go to yast once again and click on "Partitioner".

The disk is not yet formatted nor mounted so lets to that. Right click on the disk and select "Add Partition" --> "Primary Partition" --> "Maximum Size" so we can use the whole disk. --> "Operating System" --> select the file system you wish to use and the mount point.