When a firewall is placed between the ArcIMS Application Server and the Spatial Servers, the firewall may close the persistent connection during a long period of inactivity. You can set serverConnectionPingInterval in the Application Server property file to keep the connection active.
The server connection ping interval is the time interval when the Application Server will ping the Spatial Server and its server instances at lease once if inactive. For example, if an Image Server Virtual Server has four instances, the Application Server will ping each instance at least every n seconds, where n is the specified connection interval. When pinging occurs, and the Application Server debug log file is turned on, you will see the following information:
|[Feb 7, 2006 3:24:33 PM] ConnectionPinger> Pinged 4 instance(s) in Virtual Server: ImageServer1.|
If the log file states that only three instances were pinged, it means one instance was busy at that time and did not need to be pinged.
The Monitor log file, if it is turned on, records that it has been pinged as well.
|[Feb 7, 2006 3:24:35 PM] Container Connection Pinger Thread> Container: mymachine_1 was pinged.|
In the log files, you may see pinging more often that once every n seconds. This is to ensure that if there is a broken connection or unresponsive Spatial Server instance, pinging occurs at least once in the specified interval.
A secondary use for pinging is that when a Spatial Server instance does not respond for some reason, the Application Server can activate the recoveryTimeout for this instance.
The value you choose for the ping interval must be based on your firewall timeout settings. The ping value should be less than this timeout.
Windows: <ArcGIS Installation Directory>\ArcIMS\AppServer