What services are required by SQL Express/SQL Server?

Question

One of our partners recently reported that our software could not contact a remote instance of SQL Express until they started the RPC Locator and SQL Server Browser services. Where would I find a list of services that must be running, on both server and client, to enable remote access to SQL Express and/or SQL Server?

Sadly, the SQL Express documentation does not appear to include this detail.

Answer 1

Looking at my current installation of SQL Server, I have remote connections enabled and working and both RPC Locator and SQL Server Browser services are disabled on the machine.

The key is that you have to enable remote connections properly in the Surface Area Configuration Wizard.

Answer 2

I've experienced problems in the past running linked server queries if the MS DTC (Distributed Transaction Co-ordinator) service was not running

Answer 3

I don't know of any services that need to running on the client (unless they're application dependencies), but for the server, this KB article explains how to enable remote connections to SQL Server: http://support.microsoft.com/kb/914277.

By default, SQL Express is configured to only allow local connections. The gist of the article is: use the Surface Area Configuration tool to tell the SQL service to listen on tcp/ip and/or named pipes; then enable the SQL Browser service (or don't, and use a specific port in your client connection); and finally, poke a hole in your firewall. Anecdotally, I think most people have the most trouble with the firewall exceptions.

I think the RPC Locator service is more of a general windows service for handling COM calls, so I'm not sure it's fair to characterize it as a SQL-specific requirement; your app may require it to connect, but I don't know that every app would (e.g. Mitchel says that his installation works fine w/out it).

Answer 4

SQL Express always installs as a named instance (servername\sqlexpress) and hence has a dynamic port assigned to it. The SQL Browser service is required for clients to locate the instance. Without the SQL browser, a client won't know what port the service is listening on.