Anytime you change Oracle's sqlnet.ora or tnsnames.ora files, does the system require a reboot? In my instance, I only have the Oracle client installed on the machine I'm referring to, but out of curiosity what would it mean for an Oracle server installation?

2 Answers 2


In general, no. A tnsnames.ora change shouldn't require a reboot but some applications will read and parse the tnsnames.ora at startup to be able to present a drop-down list of servers to the user, for example, and will cache whatever was read when the application started up rather than re-reading the file. Depending on the situation, it might be easiest to reboot a Windows client rather than figuring out how to kill and restart any applications that might have the data cached.

A sqlnet.ora change might benefit from a reboot for the sake of consistency though it is not required. If you are doing something like enabling dead connection detection on a server by setting sqlnet.expire_time, for example, it probably makes sense to reboot the server to make sure that the setting applies to all connections rather than just new connections-- if you're trying to debug why a particular dead connection is still hanging around, knowing that the server was restarted and that you're not looking at some artifact of a connection that was opened prior to the setting being made would generally be helpful.


from my expierience wih sqlplus and some other tools:

  • tnsnames.ora is read whenever a clients wants to open a connection
  • sqlnet.ora is read whenever a client process starts up

at least for sqlplus you can verify this easily:

  • start sqlplus and then add a new entry in tnsnames.ora. you can use it.
  • start sqlplus and then configure tracing in sqlnet.ora, this should not work:
trace_directory_clint = c:\trace
trace_timestamp_client = on
trace_level_client = 16
trace_unique_client = on

But of course other application could behave in another way

Of course the trace will not work if the trace directory if the trace_directory does not exist or is not writable. so you yshould also check that your tracing works if you coigure it before you start sqlplus

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