Computer Configuration\Windows Settings\Security Settings\Local Policies\Security Options
Determines the amount of continuous idle time that must pass in a Server Message Block (SMB) session before the session is disconnected due to inactivity.
Administrators can use this policy to control when a computer disconnects an inactive SMB session. If client activity resumes, the session is automatically reestablished.
This policy is defined for servers by default in Local Computer Policy with a default value of 15 minutes. This policy is not defined on workstations.
For this policy setting, a value of 0 means to disconnect an idle session as quickly as reasonably possible. The maximum value is 0xFFFFFFFF, which means disabled.