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How to permanently delete data off a hard drive


Today I will show you how to permanently delete a file or hard drive so that data can not be recovered using data recovery tools. This comes in handy when you have sensitive data you need to get rid of.

For the purpose of this tutorial I will be using Linux Mint 17 (steps work on all Linux distributions) however if you have a Windows system boot the system with a Linux Live CD and mount the hard disk. This tutorial will show you how. Once this is done you can then use the steps outlined below.

To delete data securely we are going to use a tool called Shred.  Shred comes preinstalled on Linux so you don’t need to install it.  The following example will show you how it works.

Open up a terminal and create a file called test1 on your desktop by typing:

sudo touch /home/chris/Desktop/test1

Now we need to enter some data into the file so type:

sudo nano /home/chris/Desktop/test1

This will open up the file as shown below.  Enter whatever data you like into the file and then save and exit.

Now it is time to delete some data.  In your teminal type:

sudo shred /home/chris/Desktop/test1 

followed by:

nano /home/chris/Desktop/test1

As can be seen from the screenshot above Shred has completely scrambled all the data inside the file test1 making it unreadable.

All that is left is to delete the file so type:

sudo shred -u /home/chris/Desktop/test1

Shred will then overwrite the data 25 times with garbage while also renaming the file 11 times.  Your data is no gone.

To perform this operation on a hard drive you would open up a terminal and type the following:

sudo shred /dev/hda

where hda is your hard drive and /dev/hda is the mount point.  This would take some time to delete all the stuff on the drive so be patient.

About the Author

P1020114

Hi I’m Chris Wakefield the owner of ComTech IT Support. I provide Windows, Mac and Linux based IT Support to small businesses in Stirling, Alloa and Falkirk.

Follow @Comtech247 on Twitter

 

How to set up a DNS server on Ubuntu Server 12.04 LTS


Today I will show you how to set up a DNS server on Ubuntu Server 12.04 LTS.

The first thing to do is to install the software we need, in this case we need the bind9 package. Open up a terminal and type:

sudo apt-get install bind9

Once installed it is time for some configuring. The first file we need to configure is named.conf.local. So in the terminal type:

sudo nano /etc/bind/named.conf.local

I have used nano to open up the file but use whichever text editor you are happy with. Insert the following code into the file:

# This is the zone definition. replace example.com with your domain name
zone “comtech.com” {
type master;
file “/etc/bind/zones/comtech.com.db”;
};

# This is the zone definition for reverse DNS. replace 0.168.192 with your network address in reverse notation – e.g my network address is 192.168.0
zone “1.168.192.in-addr.arpa” {
type master;
file “/etc/bind/zones/rev.0.168.192.in-addr.arpa”;
};

Replace comtech.com with the name of your DNS domain (this is not the same as an active directory domain but rather a name for your DNS zone).

Next up is the options file. In the terminal type:

sudo nano /etc/bind/named.conf.options

Within this file we need to modify the forwarder with the address of your ISP’s DNS servers. So modify the file adding the following:

forwarders {

194.72.0.114;
194.74.65.69;
};

Replace the addresses above with the addresses of your ISP’s DNS servers.

Now we need to add the zones file:

sudo mkdir /etc/bind/zones

And then configure it:

sudo nano /etc/bind/zones/comtech.com.db (replace comtech.com with your DNS domain).

Add the following code to the file:

// replace example.com with your domain name. do not forget the . after the domain name!
// Also, replace ns1 with the name of your DNS server
comtech.com. IN SOA chris-server.comtech.com.
// Do not modify the following lines!
2006081401
28800
3600
604800
38400
)

// Replace the following line as necessary:
// ns1 = DNS Server name
// mta = mail server name
// example.com = domain name
comtech.com. IN NS chris-server.comtech.com.
comtech.com. IN MX 10 mta.example.com.

// Replace the IP address with the right IP addresses.
www IN A 192.168.1.4
mta IN A 192.168.0.3
chris-server IN A 192.168.1.4

In the above code replace the following:

comtech.com with your DNS domain name,

192.168.1.4 with your static DNS server address,

chris-server.comtech.com with your computers hostname.dns-domain,

mta is your mail server (if you have one). If you do modify the IP address to show this.

Next we have to create the reverse DNS zone file:

sudo nano /etc/bind/zones/rev.1.168.192.in-addr.arpa

Add the following code:

//replace example.com with your domain name, ns1 with your DNS server name.
// The number before IN PTR example.com is the machine address of the DNS server
@ IN SOA chris-server.comtech.com admin.comtech.com. (
2006081401;
28800;
604800;
604800;
86400
)

IN NS chris-server.comtech.com.
1 IN PTR comtech.com

All that is left to do is restart bind:

sudo service bind9 restart

Don’t forget to test the new configuration:

dig comtech.com

NOTE:

If you are unable to restart the bind9 service run the command named -g 53 which will give you a list of any configuration errors.

About the Author

P1020114

Hi I’m Chris Wakefield the owner of ComTech IT Support. I provide Windows, Mac and Linux based IT Support to small businesses in Stirling, Alloa and Falkirk.

Follow @Comtech247 on Twitter

 

 

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