Blog | Nimeshika Ranasinghe

What is a firewall? A firewall is a network security device that monitors incoming and outgoing network traffic and decides whether to allow or block specific traffic based on a defined set of security rules. Firewalls have been a first line of defense in network security for over 25 years.   A firewall can be hardware, software, or both. Why we need firewall in network? Internet connection leaves you vulnerable to hackers who want to access your financial and personal information. Some hackers may be after your high-speed connection so that they can send malicious viruses and worms, blackening your reputation. Other intruders have the power to destroy your operating system on a whim. A firewall works as a barrier, or a shield, between your computer network and internet. When you are connected to the Internet, you are constantly sending and receiving information. All messages entering or leaving the intranet pass through the firewall, which examines each m...

I want to find out login password for Ubuntu operating System.  I'm using Kali Linux. Assume that you have a word List and the username to that operating system. Black Boxed - Kali Linux  Red Boxed - Ubuntu operating system that I want to log in. 1.       Find the mac of the VM.         Right click on the VM you want to log in =>  Click Settings =>  Click Network => Expand 'Advanced'. You can Find the Mac address of the VM there. Open Kali Linux and run the following commands. 2.        Find the IP address of the  VM.      By looking at the mac address we can find out the IP address.       In here it is 3rd IP address which matches the Mac address we have found earlier.      IP - 192.168.8.102 3.        Find the open ports        In here ssh an...

The basics for a new user As a new user, you can get started with Bitcoin without understanding the technical details. Once you have installed a Bitcoin wallet on your computer or mobile phone, it will generate your first Bitcoin address and you can create more whenever you need one. You can disclose your addresses to your friends so that they can pay you or vice versa. In fact, this is pretty similar to how email works, except that Bitcoin addresses should only be used once. Balances - Block chain The block chain is a shared public ledger on which the entire Bitcoin network relies. All confirmed transactions are included in the block chain. This way, Bitcoin wallets can calculate their spendable balance and new transactions can be verified to be spending bitcoins that are actually owned by the spender. The integrity and the chronological order of the block chain are enforced with cryptography. Transactions - private keys A transaction is a transfer of value between ...

What is Bitcoin? Bitcoin is a new currency that was created in 2009 by an unknown person using the alias Satoshi Nakamoto. Transactions are made with no middle men – meaning, no banks! There are no transaction fees and no need to give your real name. More merchants are beginning to accept them: You can buy webhosting services, pizza or even manicures. Why Bitcoins? Bitcoins can be used to buy merchandise anonymously. In addition, international payments are easy and cheap because bitcoins are not tied to any country or subject to regulation. Small businesses may like them because there are no credit card fees. Some people just buy bitcoins as an investment, hoping that they’ll go up in value. Acquiring Bitcoins Buy on an Exchange Several marketplaces called “bitcoin exchanges” allow people to buy or sell bitcoins using different currencies. Mt. Gox is the largest bitcoin exchange. Transfers People can send bitcoins to each other using mobile apps or t...

Characteristics of cloud computing The essential characteristics of the cloud computing model were defined by the National Institute of Standards and technology (NIST) and have since been redefined by number of architects and experts.  A.      On-demand self-service Users are capable to providing cloud computing resources, such as server time and network storage without requiring human communication, mostly done through a web-based self-service portal. You can access to your services and you have the capability to change cloud services through an online control panel or directly with the provider. You can add or delete users and change storage networks and software as wanted. B.      Broad network access In this, capabilities are available through the network and accessed through standard tools that promote use by heterogeneous thin and thick client platform such as mobile services and workstations. They can use these devices ...

What is Cloud Computing The cloud computing paradigm is punctually gaining favor as the ideal choice for several businesses, educational and research establishments. It can be considered as a new computing model that can provide services on demand at a least cost. Cloud computing is a large scale distributed infrastructure of the hardware and software resources in the data centers that provide diverse services over the network or the Internet to satisfy user’s requirements.   According to the definition of “cloud computing” from the National Institute of Standards and Technology (NIST) it is that “cloud computing enables ubiquitous, convenient, on-demand network access to a shared pool of configurable computing resources that can be rapidly provisioned and released with minimal management effort or service provider interaction.” According to the definition, cloud computing provides a convenient on-demand network access to a shared pool of configurable computing resources l...

What is Modulation Modulation is a technique used to send information by modifying the characteristics of a basic electromagnetic signal. The basic signal is called the carrier signal. The characteristics of a signal are amplitude, frequency and phase. There are two types of modulations as: ·          Analog Modulation 1.       Frequency Modulation  (FM) 2.       Amplitude Modulation (AM) 3.       Phase Modulation (PM) ·          Digital Modulation 1.       Frequency Shift Keying (FSK) 2.       Amplitude Shift Keying (ASK) 3.       Phase Shift Keying (PSK) What is Hybrid Modulation? Hybrid modulation is a combination of ASK and PSK. This method of modulation is called Amplitude Phase Shift Keying (APSK) or Quadrature Ampl...