How To Resolve TNS Operation Timed Out Errors

Emrah BECER

Roy-Oracle

Thanks for the document posting

Yes, the DCD setting is a useful side-effect for enabling a "virtual traffic" conditions to fool the firewall into thinking there is traffic occurring between Database and Clients when in reality there is no traffic (see this link for this condition).

However, even though this is the case for "most" firewalls, some of the newer firewalls have the "intelligence" to see these DCD probe packets for what they are: simply empty probe packets and therefore not genuine traffic. As a result, setting DCD might not be effective in resetting the IDLE timer that the firewall is using (which is most likely a GOOD thing, as idle holes in a firewall are definitely not considered secure!). In such situations, you will have to work something out between your Application vendor and the firewall Admin to come to some compromise.


Kindest regards,
Roy