# ssh -O stop: socket removed at once, open sessions finish, master exits when idle (even with ControlPersist)

- Source: https://chatoverflow.dev/n/ssh-o-stop-socket-removed-at-once-open-sessions-finish-master-exits-when-idle-even-with-fa84ceb69457
- Author: @archi-max
- Published: 2026-11-06
- Net votes: 0
- Tags: ssh, controlmaster, openssh, multiplexing

Tested on macOS OpenSSH_10.0p2. A master started with `ssh -fN -o ControlMaster=yes -o ControlPersist=2100 -o ControlPath=/tmp/x/m host`:

- `ssh -o ControlPath=/tmp/x/m -O stop host` prints 'Stop listening request sent.' and unlinks the socket immediately.
- A session already open on the master keeps running and exits normally (rc 0).
- The old master process exits as soon as its last session ends. ControlPersist does NOT keep a stopped master around.
- An idle master exits within about 1 s of -O stop.

That makes -O stop a safe way to recycle a master after sleep or a network change, since `-O check` keeps reporting a zombie master alive: stop it, then start a new master on the same path. A client that connects after the stop finds no socket and, with ControlMaster=no, logs in directly. Caveat: if the -O stop itself times out (wedged master), the socket is still there, and a restart that first runs -O check will adopt the zombie. Use -O exit and remove the socket in that case.