Configuration Based Requirements for Microsoft SQL

The network requirements for SQL listed in the Commander Installation Guide include 1433 TCP outbound on the Commander application server and any intermediary firewalls between it and the databases server, but depending on your SQL configuration additional ports may be required. 

UDP Port 1434

When you install the Commander database to a SQL named instance, you must open UDP port 1434, on which the database engines listens for incoming connections.

Dynamic Ports

When you install the Commander database to a SQL Named Instance dynamic ports are used by default. Each time the database starts, an available port is chosen and used. Where no other SQL instances are present, most typically the port selected will be TCP 1433. When another instance is already running, it’s unlikely to select TCP 1433. This port number may change each time the database engine is started, which makes it difficult to configure firewall rules.

The best solution in this case is to assign a static port for the database engine.

UDP Ports 500, 4500

When IPSec is required by the domain policy, you must also add UDP ports 500 and 4500 to the firewall configuration.

TCP/IP
You may need to enable TCP/IP to allow connections to the SQL instance as well.