This feature specifies the total number of connections allowed. This is another level of security that the system administrator can configure. Many times the system administrator may want to limit the total number of connections to be a smaller value than the number of connections purchased.
The variable MaxSessions is a registry key value. This Registry key enables or disables the ability to restrict connection to the number of sessions specified. If it is disabled (0xffffffff) then all of the sessions purchased are available, otherwise, then the MaxSessions Registry value is compared to the number of sessions purchased. The smaller of the two numbers is used as the number of sessions to allow. The key is:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\GS_Tnet\Parameters\MaxSessions
The default value is 0xffffffff (That is disabled). Other values limit the number of connections allowed to the value chosen.
After you change the value for MaxSessions, it will take effect for all new connections