How does php connect to the mysql server through vpn?

How does php connect to the mysql server through a vpn? an existing mysql database server is configured with intranet access. local mysql clients must be connected through a vpn virtual network. Another apache and php server needs to connect to the mysql server data table through php. how can this problem be solved?

Reply to discussion (solution)

You can run the vpn client on that server.

This layer is generally a server layer operation.

Php should not act as the vpn client

You can run the vpn client on that server.

This layer is generally a server layer operation.

Php should not act as the vpn client

Can't I use a php program to implement a vpn connection?