Configuring SSH Keys in Ubuntu

If you need to interact with a remote server through a graphical interface, you can use VNC technology.Through a network, users can connect remotely to a server using VNC (Virtual Network Computing). It employs the RFB protocol to send screen images and input data from different devices (such keyboards and mice) and runs on a client-server architecture. Ubuntu, Windows, macOS, and other operating systems are among those that VNC supports. The ability to connect several users at once is another benefit of VNC, which can be helpful for group tasks or training sessions. Choose your server now! And if you’re looking for a reliable, high-performance, and budget-friendly solution for your workflows, Hostman has you covered with Linux VPS Hosting options, including Debian VPS, Ubuntu VPS, and VPS CentOS. In this guide, we will describe how to install VNC on Ubuntu, using a Hostman cloud server with Ubuntu 22.04 as an example. Finished installation of VNC on Ubuntu Step 1: Preparing to Install VNC Before starting the installation process on both the server and the local machine, there are a few prerequisites to review.  Here is a list of what you’ll need to complete the installation: A Server Running Ubuntu 22.04. In this guide, we will use a cloud server from Hostman with minimal hardware configuration. Hostman's plan selection in admin panel A User with sudo Privileges. You should perform the installation as a regular user with administrative privileges. Select a Graphical Interface. You’ll need to choose a desktop environment that you will use to interact with the remote server after installing the system on both the server and the local machine. A Computer with a VNC Client Installed.  At the moment, the console is the sole method of communication with a rented server running Ubuntu 22.04. You must install a desktop environment and VNC on the server in order to enable remote management through a graphical interface. The desktop environments and VNC servers that are compatible with Ubuntu servers are listed below. VNC Servers: TightVNC Server. One of the most popular VNC servers for Ubuntu. It is easy to set up and offers good performance. RealVNC Server. RealVNC provides a commercial solution for remote access to servers across various Linux distributions, including Ubuntu, Debian, Fedora, Arch Linux, and others. Desktop Environments: Xfce. A lightweight and fast desktop environment, ideal for remote sessions over VNC. It uses fewer resources than heavier desktop environments, making it an excellent choice for servers and virtual machines. GNOME. The default Ubuntu desktop environment, offering a modern and user-friendly interface. It can be used with VNC but will consume more resources than Xfce. KDE Plasma. Another popular desktop environment that provides a wide range of features and a beautiful design. The choice of VNC server and desktop environment depends on the user’s specific needs and available resources. TightVNC and Xfce are excellent options for stable remote sessions on Ubuntu, as they do not require high resources. In the next step, we will describe how to install them on the server in detail. Step 2: Installing the Desktop Environment and VNC Server To install the VNC server on Ubuntu along with the desktop environment, connect to the server and log in as a regular user with administrative rights. Update the Package List  After logging into the server, run the following command to update the packages from the connected repositories: sudo apt update Install the Desktop Environment  Next, install the previously selected desktop environment. To install Xfce, enter: sudo apt install xfce4 xfce4-goodies Here, the first package provides the basic Xfce desktop environment, while the second includes additional applications and plugins for Xfce, which are optional. Install the TightVNC Server  To install TightVNC, enter: sudo apt install tightvncserver Start the VNC Server  Once the installation is complete, initialize the VNC server by typing: vncserver This command creates a new VNC session with a specific session number, such as :1 for the first session, :2 for the second, and so on. This session number corresponds to a display port (for example, port 5901 corresponds to :1). This allows multiple VNC sessions to run on the same machine, each using a different display port. This command will ask you to create a password during the initial setup, which is necessary for users to access the server's graphical user interface. Don't forget to verify your password to run VNC on Ubuntu Set the View-Only Password (Optional)  After setting the main password, you’ll be prompted to set a password for view-only mode. View-only mode allows users to view the remote desktop without making any changes, which is helpful for demonstrations or when limited access is needed. If you need to change the passwords set above, use the following command: vncpasswd Now you have a VNC session. VNC on Ubuntu is running In the next step, we will set up VNC to launch the Ubuntu server with the installed desktop environment. Step 3: Configuring the VNC Server The VNC server needs to know which desktop environment it should connect to. To set this up, we’ll need to edit a specific configuration file. Stop Active VNC Instances  Before making any configurations, stop any active VNC server instances. In this guide, we’ll stop the instance running on display port 5901. To do this, enter: vncserver -kill :1 Simple command to stop VNC running on Ubuntu Here, :1 is the session number associated with display port 5901, which we want to stop. Create a Backup of the Configuration File  Before editing, it’s a good idea to back up the original configuration file. Run: mv ~/.vnc/xstartup ~/.vnc/xstartup.bak Edit the Configuration File  Now, open the configuration file in a text editor: nano ~/.vnc/xstartup Replace the contents with the following: #!/bin/bashxrdb $HOME/.Xresourcesstartxfce4 & #!/bin/bash: This line is called a "shebang," and it specifies that the script should be executed using the Bash shell. xrdb $HOME/.Xresources: This line reads settings from the .Xresources file, where desktop preferences like colors, fonts, cursors, and keyboard options are stored. startxfce4 &: This line starts the Xfce desktop environment on the server. Make the Configuration File Executable To allow the configuration file to be executed, use: chmod +x ~/.vnc/xstartup Start the VNC Server with Localhost Restriction Now that the configuration is updated, start the VNC server with the following command: vncserver -localhost The -localhost option restricts connections to the VNC server to the local host (the server itself), preventing remote connections from other machines. You will still be able to connect from your computer, as we’ll set up an SSH tunnel between it and the server. These connections will also be treated as local by the VNC server. The VNC server configuration is now complete. Step 4: Installing the VNC Client and Connecting to the Server Now, let’s proceed with installing a VNC client. In this example, we’ll install the client on a Windows 11 computer. Several VNC clients support different operating systems. Here are a few options:  RealVNC Viewer. The official client from RealVNC, compatible with Windows, macOS, and Linux. TightVNC Viewer. A free and straightforward VNC client that supports Windows and Linux. UltraVNC. Another free VNC client for Windows with advanced remote management features. For this guide, we’ll use the free TightVNC Viewer. Download and Install TightVNC Viewer Visit the official TightVNC website, download the installer, and run it. Download VNC from official website In the installation window, click Next and accept the license agreement. Then, select the custom installation mode and disable the VNC server installation, as shown in the image below. This is what you need to install Click Next twice and complete the installation of the VNC client on your local machine. Set Up an SSH Tunnel for Secure Connection To encrypt your remote access to the VNC server, use SSH to create a secure tunnel. On your Windows 11 computer, open PowerShell and enter the following command: ssh -L 56789:localhost:5901 -C -N -l username server_IP_address Make sure that OpenSSH is installed on your local machine; if not, refer to Microsoft’s documentation to install it. This command configures an SSH tunnel that forwards the connection from your local computer to the remote server over a secure connection, making VNC believe the connection originates from the server itself. Here’s a breakdown of the flags used: -L sets up SSH port forwarding, redirecting the local computer’s port to the specified host and server port. Here, we choose port 56789 because it is not bound to any service. -C enables compression of data before transmitting over SSH. -N tells SSH not to execute any commands after establishing the connection. -l specifies the username for connecting to the server. Connect with TightVNC Viewer After creating the SSH tunnel, open the TightVNC Viewer and enter the following in the connection field: localhost:56789 You’ll be prompted to enter the password created during the initial setup of the VNC server. Once you enter the password, you’ll be connected to the VNC server, and the Xfce desktop environment should appear. Stop the SSH Tunnel To close the SSH tunnel, return to the PowerShell or command line on your local computer and press CTRL+C. You found out how to install VNC on Ubuntu Conclusion This guide has walked you through the step-by-step process of setting up VNC on Ubuntu 22.04. We used TightVNC Server as the VNC server, TightVNC Viewer as the client, and Xfce as the desktop environment for user interaction with the server. We hope that using VNC technology helps streamline your server administration, making the process easier and more efficient. We're prepared more detailed instruction on how to create server on Ubuntu if you have some trouble deploying it. Or you can use our low-latency US based VPS! Choose your server now! Frequently Asked Questions (FAQ) How to install VNC server on Ubuntu via command line?  The most common lightweight server is TightVNC. To install it, open your terminal and run: Update lists: sudo apt update Install the package: sudo apt install tightvncserver Initialize it (and set a password) by running: vncserver How do I uninstall VNC server on Ubuntu?  To remove the software and your configuration files, follow these steps: Stop the VNC session: vncserver -kill :1 Remove the package: sudo apt remove tightvncserver --purge (Optional) Delete config files: rm -rf ~/.vnc Is VNC secure?  By default, no. VNC traffic is not encrypted, meaning passwords and keystrokes can be intercepted. It is highly recommended to tunnel your VNC connection through SSH rather than opening the VNC port (5901) directly to the internet. Why do I see a gray screen when I connect?  This "gray screen of death" usually means the VNC server doesn't know which desktop environment to load. You need to edit the ~/.vnc/xstartup file and add the command for your desktop (e.g., startxfce4 & for XFCE or gnome-session & for GNOME). Which port does VNC use?  VNC uses port 5900 + Display ID. Display :1 uses port 5901. Display :2 uses port 5902. You must ensure these ports are allowed on your firewall if you are not using an SSH tunnel. What is the difference between TigerVNC, RealVNC, and TightVNC? TightVNC: Lightweight, reliable, and great for slower connections. Very popular for Linux. TigerVNC: A high-performance fork of TightVNC, often faster on modern hardware. RealVNC: Often proprietary/commercial, offers cloud connectivity but is less common for open-source self-hosting.

Managing user permissions is crucial for system security. Ineffective access configuration often makes a system vulnerable. This guide will show you how to secure your cloud server with simple yet effective methods for managing user accounts. It is particularly useful for novice system administrators and other IT professionals. User permissions in Linux significantly impact system security. Proper configuration makes it harder for attackers to access your system. Basic User Settings Commands can be used to manage system access, creating a set of users who can read, edit, or execute data stored on the server. Ubuntu, as other Linux distributions, uses two basic user units: user and group. Let's see how to create and delete them. Creating a User A user is an individual account capable of executing commands and accessing system data. The simplest way to make a user in Ubuntu is: sudo adduser username The system will prompt you to set a password. Blocking and Deleting a User To block a user, use: sudo usermod -L username To unblock the user, replace -L with -U. To delete a user in Ubuntu: sudo userdel -r username The -r flag also removes the user’s home directory and all their data, a step that is irreversible. To retain the user’s information, omit the -r flag. Creating a Group A group is a collection of one or more accounts that share access to system data. To create a new group, enter: sudo addgroup groupname To check a user’s group memberships, use: groups username To add a user to a group in Ubuntu: sudo usermod -aG groupname username Here, -a means "add" and -G specifies the group. Deleting a Group To delete a group: sudo delgroup groupname Listing All Users and Groups To see a list of all system accounts, use: cat /etc/passwd Similarly, to see all groups: cat /etc/group Viewing User Groups and Permissions The /etc/group file contains information about all system groups and user memberships. To view all groups a user belongs to: groups username To view permissions for using sudo commands, check if the user belongs to the sudo group. Changing User Passwords To change a user’s password: sudo passwd username You will be prompted to enter a new password for the specified account. Usermod and ID Every process in the system is associated with an account identifier, indicating the user who initiated the process. By default, User IDs (UID) from 0 to 999 are reserved for system use, while newly created accounts get IDs starting from 1000. To check a user account’s properties: grep username /etc/passwd To change a user’s UID: usermod -u 2025 username To add a comment to an account: usermod -c "Comment" username To create and change the home directory: mkdir -p /catalog1/catalogusermod -d /catalog1/catalog username To change the login shell: usermod -s /sbin/nologin username Setting the login shell to /sbin/nologin prevents the user from accessing the bash shell. To set a password expiration date: usermod -e "YYYY-MM-DD" username After this date, the user cannot log in. The sudoers File and Root Permissions By default, Ubuntu grants root privileges to users for only 15 minutes to minimize security risks. The sudo command allows users to execute tasks with root privileges. Granting Root Privileges There are two main ways to set root privileges to a user in Ubuntu: Add the user to the sudo group, allowing them to execute commands with elevated privileges. Edit the sudoers file to manually assign privileges. Editing the sudoers File The sudoers file defines who has access to sudo. To edit it safely, use: sudo visudo The default contents look like this: Defaults env_reset Defaults mail_badpass Defaults secure_path="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/snap/bin" root ALL=(ALL:ALL) ALL %admin ALL=(ALL) ALL %sudo ALL=(ALL:ALL) ALL #includedir /etc/sudoers.d To add a user with root privileges: username ALL=(ALL) NOPASSWD:ALL Save the file with CTRL + X, then Y, and ENTER. Switching to Root User To switch to the root user: sudo su This combines sudo and su, allowing you to operate as the root user without prefacing each command with sudo. Creating Aliases Create user groups for simplified access management: User_Alias ADMINS = user1, user2 Use these aliases to assign permissions in the sudoers file. Interactive and Non-Interactive sudo Use sudo -i to start a shell with root privileges, useful for executing multiple commands: sudo -i File Access Management User permissions for directories and files in Ubuntu can be controlled using various commands. Adding and Removing Permissions To add permissions: chmod +rwx filename To remove permissions: chmod -rwx filename To allow execution: chmod +x filename To remove write permissions: chmod -wx filename Changing File Ownership and Group Change file ownership: chown username filename Change ownership recursively: chown -R username:group /path/to/directory Change group ownership: chgrp groupname filename Numerical Permission Codes Permissions can also be set using numerical codes: 0 = No permission 1 = Execute 2 = Write 4 = Read Basically, you add up the numbers depending on what level of permissions you want to grant. 0 = no 1 = --x 2 = -w- 3 = -wx 4 = r- 5 = r-x 6 = rw- 7 = rwx Example: chmod 777 directoryname This grants everyone permission to read, write, and execute. chmod 700 filename This grants read, write, and execute permissions only to the owner. Conclusion This guide covers user permissions management in Ubuntu and also applies to other Linux systems. By following these steps, you can create users, groups and control access to files and root privileges, enhancing your system's security. Frequently Asked Questions (FAQ) How to check user permissions in Ubuntu?  To view permissions for files and directories, use the "list long" command:ls -l The output displays a string of characters (e.g., -rwxr-xr-x) on the left side. The first character indicates the type (- for file, d for directory), and the next nine characters represent the Read (r), Write (w), and Execute (x) permissions for the Owner, Group, and Others. What is chmod 777 in Ubuntu?  chmod 777 sets the permissions of a file or directory so that everyone (Owner, Group, and Public) has full Read, Write, and Execute access. Warning: This is a major security risk. You should rarely use 777, as it allows any user on the system to modify or delete your files. What are 755 and 644 permissions?  These are the standard, secure default permissions for web servers and general usage: 755 (Directories & Scripts): The Owner has full control (Read/Write/Execute). The Group and Public can only Read and Execute (access the folder or run the script), but cannot edit or delete it. 644 (Standard Files): The Owner can Read and Write. The Group and Public can only Read. User permissions management in Ubuntu example Here is a common scenario: You want to give a user named "john" ownership of a web folder and ensure only he can edit it, while others can only view it. Change Owner: sudo chown -R john:www-data /var/www/html/site Set Directory Permissions: sudo find /var/www/html/site -type d -exec chmod 755 {} \; Set File Permissions: sudo find /var/www/html/site -type f -exec chmod 644 {} \; How do I give a user sudo (admin) permissions?  Add the user to the sudo group using the usermod command: sudo usermod -aG sudo [username] The user must log out and back in for this change to take effect. How do I view which groups a user belongs to?  Simply run the command groups [username]. If you run groupswithout a name, it shows the groups for the current logged-in user.

We are going to show you how to install PHP and PHP-FPM on Ubuntu 24.04. PHP, or Hypertext Preprocessor, is a popular open-source programming language used mostly for online development, for example on WordPress hosting. The only PHP implementation of PHP FastCGI that is really helpful for websites with a lot of traffic is PHP. At the end of this guide, you should be ready to go with PHP running on your server on our VPS hosting.  Before that, check our instruction on how to set up a server on Ubuntu.  PHP working scheme Prerequisites Before we start, please confirm you have the following: Ubuntu 24.04 LTS installed on the server A user account with the sudo access An essential command-line operation understanding A reliable internet connection for downloading software packages To ensure that your system is up to date, run the following commands: sudo apt updatesudo apt upgrade Install Apache Launch the Apache web server using the following command: sudo apt install apache2 Install PHP Let's begin with installing the PHP package in Ubuntu 24.04 server. First, open a terminal on your Ubuntu system. PHP and common modules are included in the installation action: sudo apt install php That command installs the core PHP package, the command-line interface, and common libraries. Make sure the installation works: php -v Start with PHP Installation Install PHP Extensions PHP extensions are the way to go to extending PHP installation with certain functions. Start by installing extensions: sudo apt install php-curl php-mbstring php-xml Short description: php-mysql: Allows MySQL database connection php-gd: Adds ability to manipulate images php-curl: Makes possible to communicate with servers php-mbstring: Provides multibyte string support php-xml: Enables XML support php-zip: Enables ZIP support Additional extensions can be installed as you see fit for your projects. You can search them using: apt-cache search php- Install and Configure PHP-FPM PHP-FPM is essential when dealing with high-traffic websites. To install and configure it: Install the package: sudo apt install php-fpm Launch PHP-FPM service. Depending on the installation, version number may differ. sudo systemctl start php8.3-fpm Tell PHP-FPM to go on boot: sudo systemctl enable php8.3-fpm Verify PHP-FPM is working: systemctl status php8.3-fpm This will output a response that says "Active (Running)" if everything is working as expected. Test PHP and PHP-FPM To ensure that PHP and PHP-FPM are both running with no problems, create a test file then serve it via the website's server. Let's say it uses Apache in this example: Generate PHP Info File. To show PHP settings using the phpinfo() function, do the following: mkdir -p /var/www/htmlecho "<?php phpinfo(); ?>" | sudo tee /var/www/html/info.php Set Up Apache for PHP-FPM. Ensure Apache is made compatible for PHP-FPM, by first finding Apache configuration file (usually /etc/apache2/sites-available/000-default.conf) then inserting: <FilesMatch \.php$>   SetHandler "proxy:unix:/var/run/php/php8.3-fpm.sock|fcgi://localhost/"</FilesMatch> Remember we must alter specific PHP version and socket path to suit individual settings of the server. Activate PHP and PHP-FPM. Enable PHP and PHP-FPM following these instructions: sudo apt install libapache2-mod-phpsudo a2enmod proxy_fcgi setenvif Reboot Apache. Apply changes by restarting Apache server: sudo systemctl restart apache2 Access PHP Info Page. First open your web browser and go to: http://your_server_ip/info.php Replace [server_ip] with the server IP address or domain. You can see details of your PHP installation. This is Where You Can Check Your PHP Current Status Install Multiple PHP Versions You may need to run different programs for specific projects, and each one may need a distinct set of features. Here's how to handle and work with different PHP versions on Ubuntu 24.04. First, add PHP repository: sudo apt install software-properties-commonsudo add-apt-repository ppa:ondrej/php && sudo apt update Install PHP versions you need: sudo apt install php8.1 php8.1-fpm Deselect one PHP version and select the other: sudo update-alternatives --set php /usr/bin/php8.1 If you are using multiple PHP versions, ensure that your web server is pointing to the appropriate PHP-FPM socket. Securing PHP and PHP-FPM: Best Practices As a web developer, you are aware of how crucial it is to use both PHP and PHP-FPM in secure and reliable web applications. We'll go over some security measures in this part that you should use when utilizing PHP and PHP-FPM. 1. Keep PHP and PHP-FPM Updated PHP and PHP-FPM should be up to date. Doing regular updates will eliminate known security breaches and provide overall security improvements. You need to check for updates as often as possible then update the system as soon as the updates are available. 2. Configure PHP Securely To configure PHP securely, start by disabling unnecessary and potentially dangerous functions, such as exec, shell_exec, and eval, in the PHP configuration file (php.ini). Use open_basedir directive to restrict PHP’s access to specific directories, preventing unauthorized access to sensitive files. Set display_errors to Off in production to avoid exposing error messages that could provide insights to attackers. Limit file upload sizes and execution times to reduce the risk of resource exhaustion attacks. Besides, ensure that PHP runs under a dedicated, restricted user account with minimal permissions to prevent privilege escalation. Regularly update PHP to the latest stable version to patch vulnerabilities and improve security. 3. Use Safe Error Reporting To ensure an error-free application, it is quite handy locating and correcting code bugs in a development environment. In production environment, you have the possibility to hide the PHP errors by setting the display_errors directive to be off, and you should also set the log_errors directive to be On, thus this will help you prevent PHP from showing errors to the users whereas your server will log it in a safe location without problems to users. 4. Implement Input Validation Being aware of the input validations is quite crucial during the programming of your software. Make sure that all deficiencies are tested and only SQL statements containing their SQL equivalent that can produce outwardly neutral queries via prepared statements is considered safe. 5. Secure PHP-FPM Configuration PHP-FPM is required to run using a non-usual user account with minium rights. Furthermore, access to the PHP-FPM socket or port should be very limited to the web application. 6. Enable open_basedir You need to bind open_basedir directive in order to restrict access files within the given directory. In this case, if you attempt to visit a forbidden directory and the request is accidentally transmitted to the server, PHP will prevent you from doing so. 7. Use HTTPS We need to secure web calls by making apps HTTPS-only, which is the only prominent way to block all the known hacking tricks. Installing PHP on Ubuntu 24.04 is Rewarded Conclusion With this guide, you've successfully set up PHP and PHP-FPM on Ubuntu 24.04. Your server is now configured for dynamic web applications. To maintain security and performance, remember to keep the system and packages regularly updated. If you liked this instruction, please check our Cloud Servers or low-latency US VPS to boost your cloud workflow! Frequently Asked Questions (FAQ) How do I install PHP and PHP-FPM on Ubuntu 24.04?  You can install both the core PHP and the FastCGI Process Manager (FPM) with a single command. Update your repositories and run: sudo apt update && sudo apt install php php-fpm This will install the default version, which is currently PHP 8.3. How do I enable FPM in PHP?  If you are using Nginx, FPM is enabled by default; you just need to point your server block to the socket file (usually /run/php/php8.3-fpm.sock). If you are using Apache, you must explicitly enable the configuration and the required proxy modules: sudo a2enmod proxy_fcgi setenvif sudo a2enconf php8.3-fpm sudo systemctl restart apache2 How to know if PHP-FPM is installed and running?  To verify installation, check the version: php-fpm8.3 -v To check if the service is active and running, use: sudo systemctl status php8.3-fpm You should see a green "active (running)" status. How do I enable PHP-FPM extensions?  Extensions are typically shared between the CLI and FPM. Install the extension: sudo apt install php8.3-[extension_name] (e.g., php8.3-mysql or php8.3-gd). Restart the FPM service: unlike Apache mod_php, you must restart the FPM service for changes to take effect:sudo systemctl restart php8.3-fpm Where is the PHP-FPM configuration file located?  The main global configuration file is at /etc/php/8.3/fpm/php-fpm.conf. However, the pool configuration (where you set process managers, children, and listen sockets) is located at /etc/php/8.3/fpm/pool.d/www.conf.