In addition with SEPSBE clients they are configured to go to Symantec LiveUpdate servers once per day. This is a hard coded configuration and cannot be changed.
Essentially this was implemented since SEPSBE is designed for smaller environments where a dedicated administrator may not be available. This configuration ensures that SEP clients will continue getting updated definitions if for any reason they are not able to connect to the SPC server.
As the SPC downloads content throughout the day this will be distributed to the SEP clients, so they are most likely not going to be downloading much content from our Symantec LiveUpdate servers.
Clients check for new definitions when the heartbeat into the SPC server. If a client is configured to run LiveUpdate according to a schedule, or it is manually executed on the client, it will connect to the Symantec LiveUpdate server.