SSH Connection Multiplexing

Tempest's SSH connection multiplexing reuses one authenticated connection across many sessions to the same host — instant new tabs, one MFA per host.

Tempest's connection multiplexing reuses one authenticated SSH connection across multiple sessions to the same host. New tabs to the same server open instantly — no second TCP handshake, no second SSH key exchange, no second MFA prompt — because Tempest opens additional channels on the existing connection.

This is the same idea as OpenSSH's ControlMaster auto / ControlPath, but built in and enabled with one toggle.

Enable it

Edit your SSH host → Transport section.
Toggle Connection multiplexing on.
Save and reconnect.

The first connection authenticates normally. Every subsequent tab to the same host opens a new SSH session channel on the same authenticated connection — usually < 50 ms versus seconds for a fresh handshake.

Why this is a big deal

Instant new tabs to a frequently-used server.
One MFA prompt per host, not per session — especially valuable for YubiKey / FIDO2 hosts where you'd otherwise tap-tap-tap per tab.
Faster SFTP: opening the SFTP browser doesn't kick off a fresh handshake.
Lower load on the server: one TCP socket and one auth event per active host, regardless of how many tabs you have open.

When NOT to enable it

If your server has aggressive MaxSessions limits and you frequently fan out many sessions per connection.
When using Mosh — Mosh closes the SSH channel after bootstrap, so multiplexing has nothing to share.
For one-off connections where you'll never open a second tab anyway (no benefit, slight memory cost).

Pro feature

Connection multiplexing requires Tempest Pro.

Compared to OpenSSH `ControlMaster`

Feature

OpenSSH ControlMaster

Tempest

Setup

Add ControlMaster auto + ControlPath ~/.ssh/cm/%C to ~/.ssh/config

Toggle in host edit form

Persistence across runs

Yes (until socket times out)

Per-Tempest-process

GUI to see active multiplexed connections

None

Connection panel shows session count

Combine with jump hosts

Multiplexing works through jump host chains — the chain is built once for the first session, and subsequent sessions reuse the entire chain. Particularly useful for "I have to bounce through 3 bastions to reach prod" workflows.