When exactly is the SQLNET.ORA file read? For example, if I set the SQLNET_EXPIRE_TIME = 5, does the DB check for Dead Connections every 5 minutes from that time on? Or is it by session in that every session that connects after it is set to 5 will be checked every 5 minutes?

The reason I ask is that we run our App on Citrix Servers. The Citrix Servers are bounced every night, but we consistently have sessions hanging around even after the machince has been rebooted. My understanding of DCD is that it trys to ping the machine, and if no response is received, then it will kill the session. But since the Citrix Servers are "Up" most of the day, it does no good to check for DCD during the day. What I'm thinking about doing is at the beginning of the reboot cycle (11 pm), setting it to 5 minutes so that each machine should be "pinged" for DCD while it is down so sessions can be cleaned up. But then after the reboots are over, set DCD back to 20 minutes or so.

Any other ideas?

Thanks for any help!