The OOB Server has an inactivity timer which by default is set to 7200 seconds. If a client connects to the server and does nothing for 7200 seconds (2 hours) the server will terminate that connection. This can cause problems with applications using persistent connections (e.g. PHP can do this) as if one of the connections is not used for 2 hours, it is terminated but PHP ( up to PHP 4 beta3) does not recognize this and blindly attempts to continue with the connection.
The timeouts are there to stop unnecessary connections building up and generally a useful feature. You can turn off the inactivity timeout by setting it to 0 or just increase it to the period you desire. See the question "Are there any configurable options for the OOB" for information on other OOB configurable parameters and how to set them.
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