[Ubuntu]: sudoers NOPASSWD option not working
Question: I wanted to install a package as a local user and use sudo wherever required. To do that, I created...
Network and security
How to use CONNECT Method on a HTTP Proxy using Telnet?
I generally use telnet command to test whether a given port is listening on a remote machine. For e.g., telnet...How to Install Proxychains and Access Internet via Proxy in CentOS?
If your Linux machine is behind a proxy server, then you can install Proxychains package to access internet via the given...How to Install Hping Network Security tool on CentOS7
Hping is a command line TCP/IP packet assembler/analyzer with embedded Tcl scripting functionality. Inspired by the ping command, Hping was...How to Fix DROWN Vulnerability in Apache/NGINX Web server and SMTP?
Here’s a latest vulnerability called DROWN (Decrypting RSA with Obsolete and Weakened eNcryption) that aims to attack servers using weak...How to configure a Linux Bridge to act as a Hub instead of a Switch
A bridge is a device that separates two or more network segments within one logical network. A bridge is one...[Linux]: Diagnose Network Issues using MTR – better than traceroute!
Monitoring network connectivity is an important part of server administration. Few tools like ping, traceroute are simple to use and provides valuable...[Solved]: dig: command not found – How to install dig on CentOS/Redhat/Fedora Linux using yum
Question: I followed your tutorial – how to identify the DNS server IP address configured on my CentOS 6 using the dig...How to generate Checksum of a file with different SHA2 Hash functions in Linux and Windows
Checksums are hashes used to confirm both the file integrity and authenticity. A Hash is not ‘encryption’. It is (sometimes...How to guide for cracking Password Hashes with Hashcat using dictionary method
We saw from our previous article How to install Hashcat. Also we saw the use of Hashcat with pre-bundled examples....3 Ways to Disable XML-RPC in WordPress [Security]
XML-RPC in WordPress is an useful feature that allows you to remotely publish posts via mobile phones or tablet or Windows...How to Compile and Install Python with OpenSSL Support?
Your Python installation does not support SSL? You need to compile it again after editing Setup.dist file located in the...How to Convert PPK File to OpenSSH Keys and Login using SSH in Linux?
Question: Thanks for the tutorial on “How to login to Linux instance using keys“. I used PPK key file via PuTTy...Unable to Open XEN VM Console – Virt-viewer error: cannot open display [Solved]
virt-viewer is a minimal tool for displaying the graphical console of a virtual machine. You can install virt-viewer using yum...How to Check if Bash has Shellshock Vulnerability?
Shellshock vulnerability was found during the late 2014 (to be precise, the impact was posted on CVE-2014-6271 on 24 September...RSAKeyFind Compilation (Make) Error: rsakeyfind.cpp – “memcmp, read, close” was not declared in this scope [Solved]
Question: RSAkeyfind a software written by Nadia Heninger and J Alex Halderman to find out the Cached RSA keys from memory...How to Scan your Linux Box for Trojan, Malware and Virus using ClamAV
This tutorial will take you through the ClamAV installation on CentOS, which can help you to detect Virus, Malware, Trojans...Did you Enable Bot Filtering in Google Analytics?
For the past couple of months, my website received huge number of traffic from bots, spams referrals and unusual direct...How to Block Unwanted Spam Traffic From Bad Referrer Websites like Clictune?
My website generally gets consistent web traffic – means, I don’t see big jump or downfall all of a sudden....System-config-firewall-tui does not startup on CentOS – Failed to connect to socket system_bus_socket [Solved]
Question: Hi, I’m a newbie using CentOS 6.6. I tried to configure Firewall settings via setup > Firewall Configuration. Unfortunately,...