What is DHCP?

DHCP (Dynamic Host Configuration Protocol) is a client-server network protocol that automatically assigns IP addresses within a set range. The DHCP server assigns IP addresses as they become free or unused by other members of the network. To achieve its goal a DHCP server can assign IP addresses as follows: Manual or static assignment: assigns an IP address to a specific machine. Automatic assignment: assigns an IP address to a client machine the first time it makes the request to the DHCP server and until the client releases it. And the third way to assign an IP address by a DHCP server is dynamic assignment.

So, let’s start.

Configuring DHCP Server on Rocky Linux 8 / AlmaLinux OS 8 / CentOS 8

Before we start we need to make sure that the server is fully up to date. So, connect to it and update it.

sudo dnf update

Set a static IP address on Rocky Linux 8 / AlmaLinux OS 8 / CentOS 8

The DHCP server must have a static IP address. This is important for the host to be able to do the process well. So, this is our first step.

If you need to know How to set a static IP address on Rocky Linux 8 / AlmaLinux OS 8 / CentOS 8 then you can do it through the post we have prepared for you.

After that, you can continue

Configuring the DHCP server

The package that gives us the ability to deploy the server is dhcp-server So we have to install it

sudo dnf install dhcp-server

The package is fairly lightweight so the installation can be done quickly.

Now we have to edit the server configuration file. The file in question is /etc/dhcp/dhcpd.conf but before editing it create a backup

sudo cp /etc/dhcp/dhcpd.conf /etc/dhcpp/dhcpd.confl.bak

Now proceed to edit it with your favorite text editor. I use nano but you can use vi or vim.

sudo nano /etc/dhcp/dhcpd.conf

Now add the following

default-lease-time 900;
max-lease-time 10800;
ddns-update-style none;
authoritative;
subnet 192.168.20.0 netmask 255.255.255.0 {
  range 192.168.20.10 192.168.20.200;
  option routers 192.168.20.1;
  option subnet-mask 255.255.255.0;
  option domain-name-servers 192.168.20.1;

}

Remember that all these values have to be modified. In this case, I will use some example values.

Thanks to the default-lease-time option we will be able to define how long the DHCP server will reserve an address. While the max-lease-time option will define the maximum. In this case, I have set 900 seconds or 15 minutes for default-lease-time and 10800 minutes or 3 hours for max-lease-time.

Now comes the vital part of the subnet configuration.

In this case, the subnet to configure is 192.168.20.0 and the mask is 255.255.255.0. With the range option you define the range of IP addresses to assign. And with the option router option you can define the default gateway. The subnet mask assignment to each host is defined by the option subnet-mask option. Finally, option domain-name-servers defines the DNS servers to assign to each host.

Finally, when you are done editing the file, save your changes and close the editor.

Now enable and start the option domain-name-servers service.

sudo systemctl start dhcpd
sudo systemctl enable dhcpd

You can check the status of the service,

sudo systemctl status dhcpd

In order for the dhcp service to work properly, you need to open UDP port 67 on your firewall.

Now you just need to configure the network on your client computers for this configuration.

Conclusion

A DHCP server is a simple thing to do, however, it is good to have knowledge about your network to do it correctly.

So, enjoy it!

The post How to configure DHCP Server on RockyLinux 8 / AlmaLinux OS 8 / CentOS 8? appeared first on Linux Windows and android Tutorials.

Why is it important to use a Firewall?

Although Linux is a very secure system, it is not perfect and can be attacked by an external network. Especially critical applications that make use of data such as database managers or others. Therefore, it is advisable to install a Firewall and establish adequate policies to protect your computer.

In addition to security, there is something that many people overlook and that is that in a Firewall we can not only block incoming connections but also outgoing ones. In this way, we will be able to know which applications are making connections with the Internet and make our decisions.

In Linux, there are a variety of Firewalls that can be classified as domestic or professional like PFSense. I believe that the domestic ones can work in many cases and we will work on them in this post.

How to Open Ports in Linux – Debian, Ubuntu, and derivatives

In these distributions, UFW is present by default. In case it is not then you can install it without problems.

sudo apt install ufw

After that, you can start opening ports.

The easiest way is to follow this syntax

sudo ufw allow [port]

This way, if you want to open port 26 for all protocols, just run.

sudo ufw allow 26

You can also specify a specific protocol for that port like UDP or TCP.

sudo ufw allow 26/tcp

In this case, only port 26 will be opened for the TCP protocol.

If you have to open many consecutive ports, then you can specify a range

sudo ufw allow 4000:4007/tcp

This will open all ports from 4000 to 4007 for TCP. Remember that you can change tcp to udp and enable them for that protocol.

To apply the changes run

sudo ufw reset

So, this way, you can open the ports in Debian, Ubuntu, and derivatives.

How to Open Ports in Linux – RHEL, CentOS and Fedora

Unlike Debian, Ubuntu, and its derivatives, in the RHEL family, another similar application is used to manage the Firewall and it is firewalld.

In case it is not installed, you can do it as follows

sudo dnf install firewalld

And after that, initialize it and make it run with the system.

sudo systemctl enable firewalld
sudo systemctl start firewalld

This application works with zones with public being the default zone. If we assume that this is the current zone, we can open a port as follows:

sudo firewall-cmd --zone=public --add-port=[port]/[protocol]

If you would like to open port 2122 of the TCP protocol, then you should run

sudo firewall-cmd --zone=public --add-port=2122/tcp

Unlike UFW in this case we do have to specify the protocol.

Similarly, you can specify a range of ports but still specify the protocol.

sudo firewall-cmd --zone=public --permanent --add-port=3220-3225/udp

In this case, I have opened ports from 3220 to 3225 in the UDP protocol.

To apply the changes run

sudo firewall-cmd --reload

This way you can open ports in Linux

Conclusion

Opening ports in Linux is very easy and can help you with a network problem. Also having a Firewall always increases the security of the system.

The post How to open ports in Linux? appeared first on Linux Windows and android Tutorials.

According to the project website:

webERP is a complete web-based accounting and business management system that requires only a web-browser and pdf reader to use. It has a wide range of features suitable for many businesses particularly distributed businesses in wholesale, distribution, and manufacturing.

There are 33 different language translations available all included in the archive with users all over the world.

Some of the main goals that the project planned and achieved are:

• Fast, web-based, integrated “best practice” business administration software.
• “Low footprint” efficient and fast, with absolutely minimal network traffic
• Platform Independence with no reliance on any propriety technologies
• Scripts easily readable and modifiable by a business

So, it’s time to start work

Install WebERP on AlmaLinux OS 8 / CentOS 8

The first thing you have to do, is to open a new terminal session or connect via SSH and update the distribution

sudo dnf update

Then, you have to install the LAMP stack because WebERP works as a web application. So, you can read our post about it which is compatible with AlmaLinux OS.

How to install LAMP on CentOS 8?

Also, install some modules and packages needed for the tutorial:

php php-mysqli php-curl php-curl php-json php-cgi php-xmlrpc php-gd php-mbstring unzip

Once this is installed, you can continue.

Creating a new database for WebERP

As you can imagine, this application needs to store data and for that it is compatible with advanced database drivers such as MariaDB.

Although MariaDB and AlmaLinux OS are very secure, it is advisable to create a database that is managed by a MariaDB user different from the root user.

So, open the shell

sudo mysql -u root -p

And create the database, the user, his password and the corresponding permissions.

CREATE DATABASE weberpdb;
GRANT ALL PRIVILEGES ON weberpdb.* TO 'weberpuser'@'localhost' IDENTIFIED BY 'password';
FLUSH PRIVILEGES;
EXIT;

You can replace the values with whatever you want, especially the password.

Download WebERP on AlmaLinux OS 8.4 / CentOS 8

Now, with the help of the wget command you can download the WebERP package.

wget https://sourceforge.net/projects/web-erp/files/webERP_4.15.zip

Unzip it inside the Apache folder.

sudo unzip webERP_4.15.zip -d /var/www/html

Then, make Apache the owner of the folder and set the appropriate permissions:

sudo chown apache:apache -R /var/www/html/webERP
sudo chmod 755 -R /var/www/html/webERP

Now create a new VirtualHost for webERP

sudo nano /etc/httpd/conf.d/weberp.conf

And add the following:

<VirtualHost *:80>

ServerAdmin admin@weberp.org
DocumentRoot /var/www/html/webERP
ServerName weberp.osradar.test

        <Directory /var/www/html/webERP/>
                Options FollowSymLinks
                AllowOverride All
                Order allow,deny
                allow from all
        </Directory>

ErrorLog /var/log/httpd/weberp.org-error_log
CustomLog /var/log/httpd/weberp.org-access_log common
</VirtualHost>

Replace the value of ServerName with your domain. Save the changes and close the edit

To apply the changes, restart Apache.

systemctl restart httpd

Install webERP on AlmaLinux OS

Now, open a web browser and access http://your-server/ and you will see the first screen where you will have to choose the installation language

Next, set up the database parameters

In the next step, you have to define the company name, as well as create the admin user and password.

After this, webERP will be installed and you will see the Login screen.

After logging in you will see the dashboard.

Enjoy it

Conclusion

WEbERP is a very efficient application to manage your company. The installation is easy to install and use and it’s free.

The post Install WebERP on AlmaLinux 8 / CentOS 8 appeared first on Linux Windows and android Tutorials.

AlmaLinux OS Foundation is proud to announce the release of AlmaLinux OS 8.4 Stable. One of the highlights of this release is that This is a production-ready, stable release and ready to power all your computing needs and workloads.

Also, Secure Boot is now fully supported in this release. So more and more AlmaLinux OS is becoming a solid alternative to CentOS whose support is about to end.

Some features of this release

AlmaLinux OS 8.4 is based directly on RHEL 8.4 so many of its new features are also present in this release. However, there are a few other new features that deserve to be highlighted

• OpenSCAP security profiles are now ready for production
• devel repo released with extra packages and build dependencies not included in upstream distribution. You should not enable this repository in production environments.
• PowerTools repo is now disabled by default to match upstream distribution and moved to separate file almalinux-powertools.repo

Also, several compilers such as GCC Go and Rust have been updated. This allows developers to have more up-to-date tools for these languages.

But not only this, but also Added new module streams: PostgreSQL13, MariaDB 10.5, and others.

As expected in these releases, several RHEL-related packages have been removed to give more personality to the distribution.

Where can I download AlmaLinux OS 8.4?

For now, there are only 64-bit images available, which you can download directly from a nearby mirror, although it is recommended to do so via torrent.

In case you are already using version 8.3, you just need to run a

dnf update -y

and wait for the process to finish. Also, you can migrate from CentOS 8.

Enjoy it!

The post AlmaLinux OS 8.4 available appeared first on Linux Windows and android Tutorials.

Lighttpd is a “secure, fast, compatible, and very flexible” web server optimized for high-performance environments. It consumes very few resources compared to other web servers and especially fast for running AJAX applications. It is also open source and uses a BSD license and works on UNIX-like systems, such as Linux or BSD.

A server with AlmaLinux as an operating system together with Lighttpd is a guarantee for an efficient and resource-efficient web server.

Install Lighttpd on AlmaLinux / CentOS 8

Installing Lighttpd is very easy to do but there are a few extra configurations to do.

Let’s start by adding the EPEL repository to the system because that is where the lighttpd package is hosted.

sudo dnf install epel-release

Then, you can install the program by running the following command:

sudo dnf install lighttpd

This will install the package immediately.

By default, AlmaLinux does not start the service when a program is installed. Therefore we have to do it.

sudo systemctl start lighttpd

And now make the service start with the system.

sudo systemctl enable lighttpd

Then, you can test the operation of the service with the command

sudo systemctl status lighttpd

Output

● lighttpd.service - Lightning Fast Webserver With Light System Requirements
   Loaded: loaded (/usr/lib/systemd/system/lighttpd.service; enabled; vendor preset: disabled)
   Active: active (running) since Wed 2021-04-14 16:54:29 CEST; 11s ago
 Main PID: 1247 (lighttpd)
    Tasks: 1 (limit: 12142)
   Memory: 1.1M
   CGroup: /system.slice/lighttpd.service
           └─1247 /usr/sbin/lighttpd -D -f /etc/lighttpd/lighttpd.conf

Apr 14 16:54:29 osradar systemd[1]: Started Lightning Fast Webserver With Light System Requirements.
Apr 14 16:54:29 osradar lighttpd[1247]: 2021-04-14 16:54:29: (server.c.1404) can't have more connections than fds/2:  1024 1024

Also, you can check the installed version with the command:

lighttpd -v
lighttpd/1.4.55 (ssl) - a light and fast webserver

Install PHP on AlmaLinux / CentOS 8

One way to test the performance of the webserver, you have to install PHP and make it work with Lighttpd

sudo dnf install php php-mysqlnd php-pdo php-gd php-mbstring php-fpm php-fpm lighttpd-fastcgi

Now we need to make it work with Lighttpd by editing some configuration files.

sudo nano /etc/php-fpm.d/www.conf

And modify the group and user values to be lighttpd values.

user = lighttpd
group = lighttpd

In this same file, modify the value of listen to this one

listen = 127.0.0.1:9000

Save the changes and close the file.

Now edit the /etc/php.ini file, which also needs to be modified by one value

sudo nano /etc/php.ini

And edit the cgi.fix_pathinfo value to 1.

cgi.fix_pathinfo=1

Now, make another change to the /etc/lighttpd/modules.conf file and uncomment the following line:

include "conf.d/fastcgi.conf"

Save the changes and close the editor.

Finally, we have to edit another configuration file called fastcgi.conf where we have to add the server that will listen for PHP requests.

sudo nano /etc/lighttpd/conf.d/fastcgi.conf

And add this to the end of the file

fastcgi.server += ( ".php" =>
         ((
                 "host" => "127.0.0.1",
                 "port" => "9000",
                 "broken-scriptfilename" => "enable"
         ))
 )

Again, save the changes and close the editor.

Then, restart the lighttpd service and start and enable php-fpm.

sudo systemctl restart lighttpd
sudo systemctl start php-fpm.service
sudo systemctl enable php-fpm.service

Test Lighttpd and PHP on AlmaLinux / CentOS 8

The best way to know if everything is OK is to create a PHP file and check if it is interpreted.

So, create a PHP file with any valid code such as the phpinfo method in the default root directory.

sudo nano /var/www/lighttpd/info.php

<?php
phpinfo();
?>

Save the changes and access it from a web browser, for example http://your-domain/info.php or http://ip-server/info.php.

This checks that everything is working properly.

Conclusion

Lighttpd stands out for being very light in the execution of web applications. So it can serve us for many interesting things in our daily work on a server. Today we have learned to install it on a server with Ubuntu 20.04 and we have also added support for PHP.

Please share this post and join our Telegram channel.

The post How to install lighttpd on CentOS 8 / AlmaLinux? appeared first on Linux Windows and android Tutorials.

According to the AlmaLinux website

An open-source RHEL fork built by the team at CloudLinux, inspired by the community. AlmaLinux OS is an enterprise-grade server OS, a stable Linux distribution with regular releases that come with long support windows. You can rely on AlmaLinux OS to run you and your clients’ critical workloads.

Thus, we have another RHEL-based clone, but it seems to be the best positioned to replace CentOS.

For AlmaLinux the most important thing is the community so they guarantee that it will never stop being free.

Migrating from CentOS 8 to AlmaLinux

The migration process is quite simple but there are two considerations to take into account before starting the process:

• You need to make a backup. If you use CentOS as a Workstation then LuckyBackup is a good option. In case you use it on a server you should use more professional and specific tools.

• Disable Secure Boot because AlmaLinux doesn’t support it yet. This is very important to avoid problems after the process.

  In general, the process is quite secure but it is better to be careful and take care of as much data as possible,

So, open a terminal and update the distribution

sudo dnf update

After the whole system is updated, make sure you have the curl package to download the script.

curl -O https://raw.githubusercontent.com/AlmaLinux/almalinux-deploy/master/almalinux-deploy.sh
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 12323  100 12323    0     0  50504      0 --:--:-- --:--:-- --:--:-- 50297

And then, you have to run the script as such.

sudo bash almalinux-deploy.sh

The process will take some time depending on what you have installed on your internet connection and your computer.

After the process is finished you can check the changes.

cat /etc/redhat-release

And you should get an output screen similar to this one

AlmaLinux release 8.3 (Purple Manul)

This way the migration will be complete.

The post How to migrate from CentOS to AlmaLinux? appeared first on Linux Windows and android Tutorials.