The following ports must be open to allow access to the discovery service and the database, and should suffice for most installations.
Note: If users on a Cloud Server installation type are unable to connect to the DB, please ask them to make sure that port 38476 is open on the router.
IMPORTANT: From version 4 of TaxCalc (November 2016) it is necessary to add the port 5433 (TCP) and 5432 as TaxCalc has updated the version of PostgreSQL used. This means that on any given installation the port could be either 5432 or 5433. If you are not sure which one is in use add both.