WireGuard is a modern, secure VPN protocol that can be used to set up a virtual private network (VPN) on Linux. To set up firewall rules for WireGuard, you can use the iptables command. Here’s an example of how you can set up firewall rules for a WireGuard VPN on Linux: First, you will need … Read more

In a FreeBSD server or jail, you can enable the SSH daemon (sshd) by using the service command. Here are the steps you can follow: Start by checking if the sshd service is installed by running the following command: service -e | grep ssh If the sshd service is not installed, you can install it … Read more

When you see the error “upstream sent too big header while reading response header from upstream” in the Nginx error log, it means that the response headers sent by the upstream server are larger than the buffer size allocated by Nginx to store the headers. This error can occur when the upstream server sends a … Read more

OpenSUSE is a Linux distribution that uses the YaST package manager to manage software packages. Here’s how you can install PHP on OpenSUSE 15.2/15.1: First, open the terminal and update the package repository by running the command “sudo zypper refresh” Next, install the PHP package by running the command “sudo zypper install php7” or “sudo … Read more

You can use acme.sh and Cloudflare DNS to issue a Let’s Encrypt wildcard certificate. Here are the steps you can follow: Start by installing acme.sh by running the following command: curl https://get.acme.sh | sh Next, you will need to generate an API key for Cloudflare. This can be done by visiting the “My Profile” page … Read more

Nginx is a web server and reverse proxy server that can be extended with modules. Here’s how you can list the installed Nginx modules and the compiled flags on Ubuntu and Debian Linux: To list the installed Nginx modules, use the command “nginx -V” or “nginx -V 2>&1” The command will display the version of … Read more

In Debian or Ubuntu Linux, you can use the apt-get command to download the source code of a package. Here are the steps you can follow: Start by updating the package list by running the following command: sudo apt-get update Next, you can download the source code of a package by running the following command: … Read more

On Ubuntu and Debian Linux, you can use the “apt-mark” command to hold back packages, which means that the package will not be upgraded when you run the “apt-get upgrade” command. Here’s an example of how you can hold back a package: First, use the command “apt-mark showhold” to view the list of packages that … Read more

The error message [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: unable to get local issuer certificate (_ssl.c:1091) typically occurs when the SSL certificate of the server you are trying to connect to cannot be verified. This can happen for a number of reasons, including: The certificate is self-signed, and the certificate authority (CA) that issued it is … Read more

In Arch Linux, you can install htop by using the package manager pacman. Here are the steps you can follow: Start by updating the package list by running the following command: sudo pacman -Sy Next, you can install htop by running the following command: sudo pacman -S htop Once the installation is complete, you can … Read more