A new vulnerability has been found that potentially affects most versions of the Linux and Unix operating systems, in addition to Mac OS X. Known as the “Bash Bug” or “ShellShock,” the GNU Bash Remote Code Execution Vulnerability could allow an attacker to gain control over a targeted computer if exploited successfully. And because Bash is everywhere on Linux and Unix-like machines and interacts with all parts of the operating system, everyone anticipates that it will have lot of repercussions. How does Shellshock work? Shellshock exploits a flaw in how Bash parses environment variables; Bash allows functions to be stored in environment variables, but the issue is Bash will execute any code placed after the function in the environment variable …
SSH (Secure Shell) is a network protocol that allows secure remote access to a Linux server. Normally, users authenticate using a password when connecting via SSH. However, passwordless authentication using SSH keys provides improved security and faster login access. This guide explains how to configure passwordless SSH login using PuTTY and PuTTYgen. What Is Passwordless SSH Login? Passwordless SSH authentication uses a public and private key pair instead of passwords: Once configured, you can log in securely without entering a password. Step 1: Download Required Tools Download the following utilities: Download the latest versions of putty.exe and puttygen.exe and launch PuTTYgen. Step 2: Generate SSH Keys Step 3: Upload Public Key to Linux Server Create the SSH directory if it …
It is very easy to block IP (country wise) with the help of CSF the default firewall from Cpanel.But it is not the case when we try with IPTables. In this blog I will try to demonstrate how to Block IP from a certain country with the help of IPtables.For example purpose I choose Afghanistan and China.
We can always set time to the commands showed in history command as it will be totally a security measure and can be used for troubleshooting/fingerprinting a security threat. History command sample output before setting this variable is as below: 466 df -h 467 df 468 exit 469 nfsstat 470 find / -iname *.ppt Inorder to display date and time of execution along with the commands, use inbuilt variable HISTTIMEFORMAT to set the values as shown below: #export HISTTIMEFORMAT=’%F %T ‘ where, %F for setting year/month/day %T for setting time Now, if we use the history command we can see the difference. The output will be: 500 2011-03-16 17:06:09 exit 501 2011-03-16 17:06:14 apt-get install tree 502 2011-03-16 17:06:36 tree …
The cPanel update failed with the following error : Fatal: Your RPM database appears unstable. It is not possible at the moment to install a simple RPM. The RPM database is corrupted which is causing the problem. Follow the below steps to fix this issue: 1. mkdir /root/old_rpm_dbs/ 2. mv /var/lib/rpm/__db* /root/old_rpm_dbs/ 3. rpm rebuilddb 4. Then run, #upcp –force If you require help, contact SupportPRO Server Admin
The Master Boot Record (MBR) is the first 512 bytes of a storage device. The MBR is not a partition, it is reserved for the operating system’s boot-loader and the storage device’s partition table. MBR Total Size 446 + 64 + 2 = 512 Where, 446 bytes Bootstrap. 64 bytes Partition table. 2 bytes Signature. To backup the MBR: dd if=/dev/sda of=/path/mbr-backup bs=512 count=1 To restore the MBR and partition table: dd if=/path/mbr-backup of=/dev/sda bs=512 count=1 Restoring the MBR with a mismatching partition table will make your data unreadable. To restore the MBR: dd if=/dev/zero of=/dev/sda bs=446 count=1 If you require help, contact SupportPRO Server Admin
DVDROM (Digital Versatile Disk Read-only memory) and CDROM (Compact Disc Read-only memory) are optical storage devices to store your data for future uses or for backups. Many people use these disks to store movies, photos etc. By default many older Linux machines will not allow you to see the content of them. This is due that, they are not mounted by default in your box. We have to mount them properly so that we can access their content. There are many ways to do mounting CDROM/DVDROMs. One of the classic way is to use mount command which is available in Linux. Before mounting a CDROM or DVDROM we have to check what hardware file corresponding to our disk drive. If …
Modern users expect websites to load instantly. Even a few seconds of delay can increase bounce rates and reduce conversions. For site owners running Apache servers, improving performance is essential for both user experience and search rankings. One powerful solution is mod_pagespeed, a performance optimization module originally developed by Google that automatically enhances site speed without requiring manual optimization of every file. What Is mod_pagespeed? mod_pagespeed is an extension module for the Apache Software Foundation web server that automatically optimizes website resources. It applies filters that rewrite and compress assets such as: These optimizations reduce load time, improve rendering speed, and enhance overall site performance. Why Use mod_pagespeed? Key Benefits For businesses managing multiple websites or high-traffic platforms, this module …
Log files play a critical role in Linux systems. They help administrators monitor system activity, troubleshoot issues, track application behavior, and maintain security. As systems run continuously, log files can grow very large over time. If left unmanaged, this can consume disk space and affect system performance. Logrotate is a log file management utility designed to solve this problem. It automatically rotates, archives, compresses, and removes old log files, ensuring that logs remain manageable while preserving important historical data. Log rotation can be based on file size, age, or time intervals, and it is usually handled automatically through cron jobs or systemd timers. The main purpose of log rotation is simple: to prevent log files from growing indefinitely while keeping …
Runlevel is a preset operating state on a Unix-like operating system. A run-level is a software configuration of the system that allows only a selected group of processes to exist. A system can be booted into (i.e., started up into) any of several run-levels, each of which is represented by a single-digit integer. Each run-level designates a different system configuration and allows access to a different combination of processes (i.e., instances of executing programs).