How to skip ChatGPT from WireGuard or OpenVPN on Linux

ChatGPT (short for Chat Generative Pre-trained Transformer) is a chatbot by OpenAI. It provides answers to your queries using learning techniques based on AI/ML. Unfortunately, ChatGPT deny access when connected via VPN (Virtual Private Network) such as WireGuard or OpenVPN, and you will be blocked with the following message:

Let us see how to skip the ChatGPT domain from WireGuard or OpenVPN access while you can access corporate resources behind VPN.

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A cautionary tale about locking Linux & FreeBSD user accounts

Like every other solo developer and sysadmin, I do stuff using ssh. Some stuff is automated using scripts, and others require ssh login. For example, one of my scripts logs into my Linux and FreeBSD server using public ssh keys and does a particular type of work for me. I have a dedicated user account for that purpose called autovivek on Raspberry PI 4 for Ansible and custom script automation. Here is how it works:
{rpi4:~}$ ssh autovivek@192.168.2.17 /path/to/taks1
In other cases, it sends scripts and then executes them on the remote server named 192.168.2.17. Sounds good, right? So, when I need to make backups and other tasks, I lock down the autovivek user account on the server so that it will not modify data on disks. For example, here is how to lock down a user account:
{linux-server:~}$ sudo usermod -L -e 1 autovivek
## OR ##
{freebsd-server:~}$ sudo pw lock -n autovivek

A cautionary tale about locking Linux and FreeBSD user accounts

However, I soon discovered that a user named autovivek can still log into the server and make changes despite being locked down on both Linux and FreeBSD servers.

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How to configure static IP address on Alpine Linux

At home or in a cloud environment, IP addresses are assigned dynamically by the DHCP server. Setting a static IP address on your Alpine Linux server is required for various reasons. For instance, Alpine Linux is configured as a DHCP server or KVM server to host multiple VMs. Static IP address makes it easy to work with port forwarding, firewalling, and HTTPS server too. This quick tutorial will explain how to set up a static IP address on Alpine Linux.

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How to find NetworkManager version on Linux

How do I check or find NetworkManager version on Linux distribution?

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Linode cloud firewall: Do you need it to protect the Linux server?

Linode is an original cloud platform and founded before AWS. Back then, we used to call them VPS (Virtual Private Server). Recently they added a new firewall feature to control network access to my Linode server from the Cloud. Let us test drive Linode cloud firewall.

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How to unlock LUKS using Dropbear SSH keys remotely in Linux

On Linux, we encrypt our partitions and entire disk using Linux Unified Key Setup-on-disk-format (LUKS) for security and privacy reasons. We unlock LUKS protected disk by providing a passphrase at boot time. You need to be in front of your computer or use a remote console to open the encrypted disk under Linux at boot time. However, if your system is in the basement, remote datacenter/office, or upstairs office, you won't able to unlock and boot your Linux box. We can use the Dropbear SSH server for LUKS encrypted Debian or Ubuntu or any other Linux distro via SSH to solve this problem. Let us see how to unlock LUKS using Dropbear SSH keys in Linux at boot time.

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Significant vulnerabilities that crippled IT world this decade (2010-2020)

The last ten years in the computer and IT security world are crippled with so many vulnerabilities. We saw massive cloud computing adoption and end-users using mobile devices with high speed 4G LTE networks. A threat actor may have exploited such weakness in modern computers and networks. Let us look into top vulnerabilities and the attack surface in this decade (2010-2020) that affected Linux/Unix, macOS, IT, cloud-computing, and computers in general.

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How to show dropped packets per interface on Linux

How do I display dropped packets per interface on Linux operating systems from the command line option? How can I determine why a Linux server is dropping packets?

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How to disable firewall and NAT rules on the LXD bridge

I followed your Ubuntu LXD tutorial, and I noticed LXD automatically created firewall and NAT rules. Is there any way to disable this feature? I want to manage a firewall using custom rule sets. How can I disable firewall and NAT rules on the LXD bridge under Linux?

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Ubuntu 20.04 add network bridge (br0) with nmcli command

How do I configure my Ubuntu 20.4 LTS and add network bridge (br0) with the nmcli command? How can I create a Linux network bridge on Ubuntu Linux 20.04 LTS server for KVM (Kernel-based Virtual Machine)?

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Curl Shell Script To Purge Cache From Stackpath CDN

A content delivery network or content distribution network (CDN) is a system of servers containing copies of data, placed at various points in a network so as to maximize bandwidth for access to the data from clients throughout the network. Please note that the following script will only work with Stackpath CDN. You need to get API access keys using stackpath portal.

CentOS 8 add network bridge (br0) with nmcli command

How do I configure my CentOS 8 and add network bridge (br0) with the nmcli command? How can I create a Linux network bridge on CentOS Linux 8 server for KVM (Kernel-based Virtual Machine)?

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How to install Squid Proxy Server on Ubuntu 20.04 LTS Linux

How do I install Squid Proxy Server on Ubuntu 20.04 LTS Linux server for web clients? How can I filter out internet traffic for LAN users such as blocking domains, unwanted URLs, office hours for Internet access, and more using Squid running on Ubuntu server?

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Letsencrypt is revoking certificates on March 4

Let's Encrypt is a non-profit certificate authority that provides X.509 certificates for Transport Layer Security (TLS) encryption free of cost. The TLS certificate is valid for 90 days only. However, Due to the bug, they need to revoke many (read as "certain") Let’s Encrypt TLS/SSL certificates. Let us see how to find out if you are affected by this bug and how you can fix it to avoid any problems with your TLS/SSL certificates.

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Linux bind IP that doesn’t exist with net.ipv4.ip_nonlocal_bind

How do I allow Linux processes to bind to IP address that doesn't exist yet on my Linux systems or server?

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How to see Time-To-Live (TTL) for a DNS record

How do I see Time-To-Live (TTL) for a DNS record using Linux, macOS, *BSD, or Unix-like systems command line option? How do I find my DNS TTL?

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How to test and validate DNSSEC using dig command line

How do I test and validate DNSSEC using the dig command line under Linux, macOS, *BSD, and Unix-like systems?

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How to install and use Nginx on CentOS 8

How do I Install Nginx on CentOS 8 Linux server? How can configure the latest version of Nginx web server on a CentOS Enterprise Linux 8 server using the CLI and host a static site?

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How to set up a firewall using FirewallD on CentOS 8

I am a new CentOS Enterprise Linux 8 sysadmin. How do I set up a firewall using FirwallD on CentOS 8?

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How to check open ports in Linux using the CLI

I need to list all open ports in Linux cloud server. How do I check open ports in Linux using the CLI? Can you give me the command to check open ports in Linux operating system?

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Linux disable firewall command

I am a new Linux system administrator. I have a hardware-based firewall, so I don't need a firewall on each server. How do I disable the firewall on Linux?

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How do I check if a port is in use on Linux?

I am a new Linux system user. I need to find out which process is listening on a port on Linux using the command line. How do you find out which process is listening on a port on Linux operating systems?

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Shell script to set up an LXD (Linux Containers) VM lab for testing purpose

A sample shell script to build an LXD (Linux Containers) VM lab on Ubuntu Linux 16.04 LTS server.

Linux/Unix bash shell script to purge Cloudflare url/images from the command line

Here is a simple and easy to use bash shell script to purge/delete Cloudflare url/images cache from the command line without using web interface.

How to set up a firewall using FirewallD on RHEL 8

I am a new Red Hat Enterprise Linux sysadmin. How do I set up a firewall using FirwallD on RHEL 8?

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How to configure a static IP address on RHEL 8

I am a new sysadmin and RHEL 8 user. My system is configured to use DHCP. How can I switch from DHCP to a static IP address on RHEL 8 system? How do I setup a static TCP/IP address on my Red Hat Enterprise Linux 8 server using command line option?

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