How to repair grub bootloader on a dual boot machine with Windows and Linux

Grub 2 typically gets overridden when you install Windows or another Operating System. To make Linux control the boot process, you need Reinstall (Repair/Restore) Grub using a Linux Live CD.

ROOT_DISK='/dev/sda2'
BOOT_DISK='/dev/sda1' # optional, only for EFI
DISK='/dev/sda'

mount $ROOT_DISK /mnt
mount $BOOT_DISK /mnt/boot/efi # optional

for i in /dev 
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Restricting Access with HTTP Basic Authentication in Apache and Nginx

You can restrict access to your website or some parts of it by implementing a username/password authentication. Usernames and passwords are taken from a file created and populated by a password file creation tool, for example, apache2-utils.

Creating a Password File

sudo htpasswd -c /etc/httpd/.htpasswd admin
or
sudo htpasswd -c 
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IP based restriction using Nginx

You can restrict access to certain parts of your website using Nginx’s inbuilt authentication and authorization mechanism based either on your client’s I.P, by prompting for a login prompt or both.

A sample I.P. based authorization configuration would be like:

location /private/ {
allow 192.168.1.1/24;
allow 172.16.0.1/16;
allow 127.0.0.1;
deny 
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Use NGINX as a Reverse Proxy

A reverse proxy is a server that sits between internal applications and external clients, forwarding client requests to the appropriate server. While many common applications, such as Node.js, are able to function as servers on their own, NGINX has a number of advanced load balancing, security, and acceleration features that … Read more

How to Redirect www URL to non-www and non-www URL to www with Nginx

This tutorial will show you how to redirect a www URL to non-www, e.g. www.example.com to example.com, with Nginx. We will also show you how to redirect in the other direction, from a non-www URL to www.

Configure DNS Records

In order to set up the desired redirect, www.example.com to … Read more

How to Redirect HTTP to HTTPS in Nginx

All login credentials transferred over plain HTTP can easily be sniffed by a MITM attacker, but it is not enough to encrypt the login forms. If you are visiting plain HTTP pages while logged in, your session can be hijacked, and not even two-factor authentication will protect you. To protect … Read more

named bind server – adding multiple TXT records for the same domain

named bind server – adding multiple TXT records for the same domain

_acme-challenge IN      TXT "JoM6ibdd4vWEwiYNj4XRSftAL1XD1w5WNrHFiRs_Hn-U"
_acme-challenge IN      TXT "6EmvVKhLSn40QKDtGFZXyVPYnSIe1OiD1TSyYkE_yd8g"

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