Shodh for Truth

P. V. Narasimha Rao became the Prime Minister of India in 1991 shortly after the assassination of Rajiv Gandhi during the election campaign. He inducted Dr. Manmohan Singh, the then former governor of the Reserve Bank of India and former deputy chairman of the Planning Commission as the Finance Minister in the new cabinet. They spearheaded the 1991 economic reforms and liberalization which opened up the economy for foreign investments and ended the license permit raj. Crucially, it triggered the Indian economy to grow at a much faster pace than the embarrassing 3.5% Hindu rate of growth as some would mockingly term it. While Mr. Rao needs to be remembered for this pivotal moment in the short history of Independent India, there is another incident that happened at the fag end of his political career which is the topic of interest of this article. There was a case of corruption filed against Mr. Rao in 1996 after the completion of the term of the government. There are two interesting leg...

The /etc/hosts file is a powerful mechanism for managing the information about hosts in the local network in the absence of a local DNS server. Setup We have 4 VMs in the local /24 network. The following are the details: vm-1-ubuntu-16-04 - 10.0.1.11 vm-2-ubuntu-16-04 - 10.0.1.12 vm-1-ubuntu-18-04 - 10.0.1.21 vm-2-ubuntu-18-04 - 10.0.1.22 The VMs are reachable via their IP address but not by their hostnames. This is problematic because we have to remember their IP addresses everytime we want to access these hosts. It is would be much simpler to remember and access the servers by their hostnames. For that we need some sort of mapping between the IP addresses and their corresponding host names. There are 3 common ways of achieving this mapping. Setup a DNS server which handles resolution for your local network. Use an existing DNS server of the local Internet Service Provider (ISP) or any other higher level ISP. Note that a public static IP address is required for this s...

This article explains the simplest method to set hostname and Fully Qualified Domain Name (FQDN/fqdn) of any given system using hostnamectl Check that hostnamectl is present on the system by typing it in a shell. You will see output similar to the one given below. In case hostnamectl is not found, it is a good idea to install it. sudo apt update sudo apt install systemd-services Verify the static hostname given above using the following command: Also verify it by checking /etc/hostname file Change the hostname and set the desired hostname by running the following command and authenticating with the password. hostnamectl set-hostname <hostname> Start a new shell session or reconnect to the server to see the change in the hostname Again run above steps to verify that hostname has been changed correctly. Configure FQDN While the above process may suffice to identify the host in the local network, it is not enough when the host is to be identifi...

nmap or network mapper is a great open-source tool for network scanning and port discovery. The detailed description of nmap is available on its official website . An interesting fact about nmap and its wide ranging applications from the website :p "...It was even featured in twelve movies , including The Matrix Reloaded , Die Hard 4 , Girl With the Dragon Tattoo , and The Bourne Ultimatum ." Hoping that this has generated enough curiosity in you, lets focus on the very basic use of nmap in network subnet scanning. Network scanning is useful to detect hosts in the network that are reachable from the server on which nmap is run. It is also useful in security auditing of the servers exposed to internet. We have a setup of 4 VMs on a local network with each having an IP address. The local network subnet is defined as 10.0.1.1/24 and the IPs in the below images verify this fact. The goal is to verify that nmap is able to detect all the hosts in the local subnet 10...