Originally posted by axe
Alert.log does not show any errors. Listener is not going down. The only other thing is the sqlnet.log shows TNS-12547 and TNS-12537. This error occurs for such a small period of time that by the time we notice it it no longer is a problem.
Look in the sqlnet.ora and the listener.ora for a timeout parameter. If there is a timeout parameter you may want to either increase the number or set it to 0 for infinite. It could be that from time to time there is an increase in network latency If Oracle doesn't wait long enough it might give you that error message. Just a thought.