Beginning July 29, 2025, HECC enclave front-end systems will enforce agency mandated session timeout restrictions: SSH connections to front-end sytems will disconnect after 15 minutes of inactivity.

Every shell is subject to a 15-minute idle session timeout unless other utilities are used that allow you to have persistent sessions on the front ends that can be used to reestablish access if your connection is interrupted.

We strongly encourage users to use the tmux or screen commands. Both of these “terminal multiplexer” software packages support the new idle timeout session scheme. For example, if you connect to a front end via SSH and then run tmux, your job will still be disconnected after 15 minutes of inactivity—however, you can then reconnect via SSH, run tmux attach, and return to you prior work. Importantly, the shells running inside the TMUX “panes” are not subject to the 15-minute idle session timeout, and you will not lose any work.

For more information, including best practices for minimizing the impact to your interactive sessions, see the Knowledge Base article, Using the Screen or tmux Commands.

If you encounter any issues or require assistance to adjust to these new settings, please contact the Control Room at (800) 331-8737, (650) 604-4444, or support@nas.nasa.gov.