To generate an RSA SSH key pair on a Linux system, you can use the ssh-keygen command, which is included with most Linux distributions. Here are the steps to generate an RSA SSH key pair: Open a terminal or command prompt on your Linux system. Type the following command to generate an RSA key pair: … Read more

To generate strong passwords in Linux or UNIX systems using the /dev/urandom device, you can use the tr command to translate random bytes into printable characters. Here’s an example command that generates a random 12-character password using /dev/urandom: tr -dc A-Za-z0-9 < /dev/urandom | head -c 12 ; echo ” This command uses tr to … Read more

The error message “ERROR 1018 (HY000): Can’t read dir of ‘./dbname/’ (errno: 13)” indicates that the MySQL server is unable to read the directory where the database files are stored, due to a file permissions issue. Here are some steps to resolve the issue: Check the permissions of the directory and its contents using the … Read more

To change the password of a user in FreeBSD using a shell script, you can use the passwd command. Here’s an example shell script that prompts for a username and new password: #!/bin/sh # Prompt for the username echo “Enter the username: ” read username # Prompt for the new password echo “Enter the new … Read more

Postfix is a popular mail transfer agent (MTA) used for routing and delivering email messages between mail servers. By default, Postfix logs the client IP address and hostname in its mail logs, which can be useful for troubleshooting and analysis. However, if you want to hide the client IP address or hostname from the mail … Read more

To forward emails received by a Postfix mail server to another email account, follow these steps: Edit the Postfix configuration file /etc/postfix/main.cf: # vi /etc/postfix/main.cf Add the following line to the end of the file to specify the email address to which emails should be forwarded: virtual_alias_maps = hash:/etc/postfix/virtual Create a new file /etc/postfix/virtual and … Read more

OpenNTPD is a free and easy-to-use implementation of the Network Time Protocol (NTP) that provides accurate time synchronization between servers and clients on a network. Here are the steps to install OpenNTPD on FreeBSD: Update the package repository: # pkg update Install OpenNTPD: # pkg install openntpd Edit the configuration file /etc/ntpd.conf to specify the … Read more

Keychain is a utility that manages SSH keys in a convenient and secure way. It can be used to set up secure passwordless SSH access for backup scripts on Linux. Here are the steps to use keychain to achieve this: Install keychain on your Linux system. On Debian/Ubuntu, you can use the following command: sudo … Read more

In FreeBSD, you can disable the hardware bell, also known as the system beep, by setting the hw.syscons.bell parameter to 0. This parameter can be set in the /boot/loader.conf file, which is read during the boot process. Here are the steps to disable the hardware beep in FreeBSD: Open a terminal window or SSH into … Read more

TCP Wrappers is a security feature in Unix-based systems that provides access control and authentication for network services. TCP Wrappers allow you to specify which hosts or networks are allowed to connect to your services, and which services they are allowed to use. You can find out if a program is compiled with TCP Wrappers … Read more