How to Set Connection Limits
A virtual server can accept an unlimited number of inbound connections and is limited only by the resources of the computer where the virtual server is running. To prevent a computer from becoming overloaded, you can limit the number of connections that can be made to the virtual server at the same time. By default, Microsoft® Exchange does not limit the number of incoming connections.
After users are connected, you can also limit the length of time that idle connections remain logged on to the server. By default, Exchange disconnects idle sessions after 10 minutes.
Before You Begin
In topologies that contain Exchange front-end and back-end servers, the connection time-out setting varies based on server role. On back-end servers, the connection time-out setting limits the length of time clients can be connected to the server without performing any activity. However, on front-end servers, the connection time-out setting limits the total length of the client session, regardless of client activity. Therefore, in front-end and back-end server environments, you should configure the time-out value on your front-end servers high enough so that users can download the maximum message size that is permitted over the slowest connection speed that you want to support. Setting this value high enough ensures that clients are not disconnected while they are downloading messages.
Setting the connection time-out setting too low can cause clients to be unexpectedly disconnected from the server and possibly receive error messages. Thirty minutes is the lowest recommended connection time-out setting.
To set connection limits
Log on to the Exchange server where the virtual server is running using the Exchange administrator account that has local Administrator permissions and Exchange Full Administrator permissions.
In Exchange System Manager, expand Protocols, right-click the protocol for which you want to change connection limits, and then click Properties.
On the General tab, set the appropriate connection limits.