Here is the definition of a database according to the dictionary:

Structured set of files regrouping information having certain characters in common; software allowing to constitute and manage these files.

The data contained in most common databases is usually modeled in rows and columns in a series of tables to make data processing efficient.

Thus, the data can be easily accessed, managed, modified, updated, monitored and organized. Most databases use a structured query language (SQL) to write and query data.There are some free database hosting services provided by some online company or organizations. This post collects some popular ones and compares them quickly with some personal notes. 

 Free MySQL Databases:
    • a testing environment
    • no more than 200MB data
    • one MySQL DB
    • phpMyAdmin
  •  – connection failed, no space (March 17 2023)
    • Instant activation.
    • Free 100MB database size.
    • phpMyAdmin
    • No query limits.
    • Unlimited bandwidth.
    • Suitable for testing/develoment use only.
    • 1 DB
    • DB space starting from 5MB
    • phpMyAdmin
    • Multiple server locations
    • Instant account activation
    • Remote connections allowed
    • MySQL 8 DB
    • PhpMyAdmin
    • One DB, 50MB storage
    • Only for testing
    • No root access
Some free MYSQL DB from Free Hosting Company, but only limted only for internal or localhost connections:

Free Online Postgres DB

Free Postgres DB
  • – Supabase is an open source Firebase alternative. Start your project with a Postgres database, Authentication, instant APIs, Edge Functions, Realtime subscriptions, and Storage.
    • Up to 500MB database & 1GB file storage
    • Up to 2GB bandwidth
    • Up to 50MB file uploads
    • Social OAuth providers
    • 50,000 monthly active users
    • Up to 500K Edge Function invocations
    • 1-day log retention
    • Community support
  • Firebase:  – The Firebase Realtime Database is a cloud-hosted NoSQL database that lets you store and sync data between your users in realtime. NEW: Cloud Firestore enables you to store, sync and query app data at global scale. Further limitation for free Spark Plan can be found from pricing page:
    • Cloud Firestore
      • 1GB total stored data
      • 10GB/month Network egress
      • 20K writes/day : Document writes
      • 50K reads/day :  Document writes
      • 20K delete/day : Document delets
    • Realtime DB
      • 100 simultaneous connections
      • 1GB stored
      • 10GB/month downloded
      • no multiple db per project
    • Hosting
      • 10GB storage
      • 360MB/day data transfer
      • Custom domain/ssl
      • multiple sites per project
Following section is coming from

Allow Remote Connections to MySQL

Allowing connections to a remote MySQL server is set up in 3 steps:

  1. Edit MySQL config file
  2. Configure firewall
  3. Connect to remote MySQL server

Step 1: Edit MySQL Config File

1.1 Access mysqld.cnf File

Use your preferred text editor to open the mysqld.cnf file. This example uses the nano text editor in Ubuntu 18.04. Enter the following command in your command-line interface to access the MySQL server configuration file:

sudo nano /etc/mysql/mysql.conf.d/mysqld.cnf

The location of the file may vary based on the distribution and version in use. If the MySQL configuration file is not it its default location try using the Linux find command to detect it.

1.2 Change Bind-Address IP

You now have access to the MySQL server configuration file. Scroll down to the bind-address line and change the IP address. The current default IP is set to This IP limits MySQL connections to the local machine.
The new IP should match the address of the machine that needs to access the MySQL server remotely. For example, if you bind MySQL to, then any machine that reaches the MySQL server can also connect with it. For this website to access it you need to use IP address
Once you make the necessary changes, save and exit the configuration file.

Note: Remote access is additionally verified by using the correct credentials and user parameters you have defined for your MySQL users.

1.3 Restart MySQL Service

Apply the changes made to the MySQL config file by restarting the MySQL service:

sudo systemctl restart mysql

Next, your current firewall settings need to be adjusted to allow traffic to the default MySQL port.

Step 2: Set up Firewall to Allow Remote MySQL Connection

While editing the configuration file, you probably observed that the default MySQL port is 3306. This is default MySQL port number but can be changed in the config file.

If you have already configured a firewall on your MySQL server, you need to open traffic for this specific port. Follow the instructions below that correspond to your firewall service in use.

Option 1: UFW (Uncomplicated Firewall)

UFW is the default firewall tool in Ubuntu. In a terminal window, type the following command, changing remote_ip_address to the required IP address, to allow traffic top the IP and port:

sudo ufw allow from remote_ip_address to any port 3306

The system confirms that the rules were successfully updated. Firewall rule added to firewall deamon.

Option 2: FirewallD

The firewalld management tool in CentOS uses zones to dictate what traffic is to be allowed.
Create a new zone to set the rules for the MySQL server traffic. The name of the zone in our example is mysqlrule, and we used the IP address from our previous example

sudo firewall-cmd --new-zone=mysqlrule --permanent
sudo firewall-cmd --reload
sudo firewall-cmd --permanent --zone=mysqlrule --add-source=
sudo firewall-cmd --permanent --zone=mysqlrule --add-port=3306/tcp
sudo firewall-cmd --reload

You have successfully opened port 3306 on your firewall.

Option 3: Open Port 3306 with iptables

The iptables utility is available on most Linux distributions by default. Type the following command to open MySQL port 3306 to unrestricted traffic:

sudo iptables -A INPUT -p tcp –dport 3306 -j ACCEPT

To limit access to a specific IP address, use the following command instead:

sudo iptables -A INPUT -p tcp -s –dport 3306 -j ACCEPT

This command grants access to You would need to substitute it with the IP for your remote connection.
It is necessary to save the changes made to the iptables rules. In an Ubuntu-based distribution type the following commands:

sudo netfilter-persistent save
sudo netfilter-persistent reload

Type the ensuing command to save the new iptables rules in CentOS:

service iptables save

Step 3: Connect to Remote MySQL Server

Your remote server is now ready to accept connections. You can now use this site to connect to your MySQL databases, using your server IP, username and password.

How to Grant Remote Access to New MySQL Database?

If you do not have any databases yet, you can easily create a database by typing the following command in your MySQL shell:


To grant remote user access to a specific database:


The name of the database, the username, remote IP, and password need to match the information you want to use for the remote connection.

How to Grant Remote Access to Existing MySQL Database

Granting remote access to a user for an existing database requires a set of two commands:

update db set Host=’' where Db='yourDB';
update user set Host=’' where user='user1';

User1 is now able to access yourDB from a remote location identified by the IP

Connect to MySQL DB

Install MySQL Client in Linux server:

apt install mysql-client-core-8.0

From linux console, type following command to connect to your DB server and DB:

$ mysql -h {hostname} -u username -p {databasename}
Password: {your password}

By netsec

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