You can control which port to connect to inbound VPS server from the access allowed ports section in the accordion of the network information.

Permit All Access: It allows all port numbers to connect to.
SSH: It only allows port number 22.
Web: It allows either port number 80 or 443.
Mail: It allows port number 25, 110, 143, 465, 587, or 995.
MySQL: It only allows port number 3306.
PostgreSQL: It only allows port number 5432.
RDP: It only allows port number 3389.

The initial setting of access allowed ports of the outbound are set as [Allow All].
Access allowed ports of the outbound can be set in the API admin.