How to fix ERROR 1130: Host is not allowed to connect in MySQL

Connect to MySQL as root or another privileged user and query the mysql.user table to see what hosts the user is allowed to connect from:

SELECT Host, User FROM mysql.user WHERE User = 'your_username';

If you only see 'localhost' or '127.0.0.1', this explains why remote connections are rejected. The user needs explicit host entries or a wildcard entry.

To allow a user to connect from a specific IP address, execute this command (replace placeholders):

GRANT ALL PRIVILEGES ON database_name.* TO 'username'@'192.168.1.100' IDENTIFIED BY 'password';
FLUSH PRIVILEGES;

Or if the user already exists, update permissions without changing the password:

GRANT ALL PRIVILEGES ON database_name.* TO 'username'@'192.168.1.100';
FLUSH PRIVILEGES;

Replace 192.168.1.100 with the actual client IP address.

To allow a user to connect from any host, use the wildcard character (%):

CREATE USER 'username'@'%' IDENTIFIED BY 'password';
GRANT ALL PRIVILEGES ON database_name.* TO 'username'@'%';
FLUSH PRIVILEGES;

Or grant to existing user:

GRANT ALL PRIVILEGES ON database_name.* TO 'username'@'%';
FLUSH PRIVILEGES;

WARNING: Using '%' for all hosts increases your security surface. Only use this if necessary, and consider combining it with REQUIRE SSL for encrypted connections:

GRANT ALL PRIVILEGES ON database_name.* TO 'username'@'%' REQUIRE SSL;
FLUSH PRIVILEGES;

After granting privileges, verify that the user can now connect from the intended host:

SELECT Host, User FROM mysql.user WHERE User = 'username';

You should now see the new host entry (either the specific IP or '%'). Test the connection from the client machine:

mysql -h mysql_server_ip -u username -p database_name

If the MySQL server is not listening on the correct network interface, no remote connections will work. Edit the MySQL configuration file:

- On Linux: /etc/mysql/mysql.conf.d/mysqld.cnf or /etc/mysql/my.cnf
- On macOS: /usr/local/etc/my.cnf or /opt/homebrew/etc/my.cnf
- On Windows: C:\ProgramData\MySQL\MySQL Server 8.0\my.ini

Locate the [mysqld] section and check the bind-address setting:

[mysqld]
bind-address = 127.0.0.1

To listen on all interfaces, change it to:

[mysqld]
bind-address = 0.0.0.0

Or to listen on a specific IP:

[mysqld]
bind-address = 192.168.1.50

After editing, restart MySQL:

sudo systemctl restart mysql

Ensure that the client can reach the MySQL server on the correct port (default 3306):

telnet mysql_server_ip 3306
nc -zv mysql_server_ip 3306

If the connection times out, check firewall rules on the server:

# On Linux (iptables)
sudo iptables -L -n | grep 3306

# Or check with ufw if enabled
sudo ufw status
sudo ufw allow 3306

On cloud platforms (AWS, GCP, Azure), verify security group rules or network ACLs allow inbound traffic on port 3306 from your client IP.