The max number of active connections supported with a Forum Sentry appliance is 16384. This is total connections. There is no specific limit for each listener or remote policies. However, you can set connection limits to specific remote servers on the HTTP Remote policies.
Note: Test/Dev systems have a 5 concurrent connections limit built into the licensing. You can verify this on the General Info page under license features, which should show 5 or Unlimited Concurrent Connections.