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

1. Edit your SSH host → Transport section.

2. Toggle Connection multiplexing on.

3. 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.

See also

• SSH Jump Host & Bastion Chaining

• YubiKey & FIDO2 SSH Authentication — multiplexing means one tap per host instead of per session