Newbie Q: Do sqlnet.ora changes require server reboot?

Im looking into using sqlnet.expire_time for an application that sends batch processing overnight. we have had some issues with large batch files coming over to the database completing, but on the application side not showing as completed. my guess is that the firewall has a time out, so instead of having a code change on the third party app, i wanted to poll the app server for "Still Kicking"

Is this the right approach?
more general, do sqlnet.ora changes require severver reboot, instance bounce, listener bounce?

Thanks
DBA Wannabe

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