@arifulhb

You don’t specifically need to setup a tunnel to connect to from D1 (Web) to D2 (DB). You can change the port that MySQL binds to in MySQL’s configuration file and set it to the private network IP – then restart MySQL.

Specifically, you’d be looking for bind-address. So if your private network IP is 10.0.0.2, you’d then set the bind-address like so:

bind-address = 10.0.0.2

Then service mysql restart.

You would then need to create a user for the connecting host. So if your web server has a private IP of 10.0.0.1, then you’d do:

create database name_of_db;

grant all on name_of_db.* to 'name_of_user'@'10.0.0.1' identified by 'password';

name_of_db = name of database

name_of_user = name of database user

password = password for database user

You’d then use those credentials and the private IP of the database server to connect to MySQL.

Hi @arifulhb

Even with SSH over the private networking, there will still be some lag. Have you considered connecting directly over the private networking for MySQL?
https://www.digitalocean.com/community/tutorials/how-to-set-up-a-remote-database-to-optimize-site-performance-with-mysql

If you activated the firewall at one point, that might be what’s blocking you currently.

sudo ufw status

You can check what services are listening on the different interfaces with this command:

sudo lsof -iTCP -sTCP:LISTEN -P