> ## Documentation Index
> Fetch the complete documentation index at: https://undyingterminal.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Jumphost

> Use a bastion host to reach private machines and keep sessions persistent across disconnects.

## When to use a jumphost

Use a jumphost (bastion host) when your target machine is only reachable from a private network, but you have SSH access to an internet-reachable host inside (or adjacent to) that network.

## Basic SSH jump

Use OpenSSH's jump option:

```bash theme={null}
ssh -J user@jumphost user@target
```

If you need a non-standard port for the jumphost:

```bash theme={null}
ssh -J user@jumphost:2222 user@target
```

## Recommended SSH config

Add host aliases to `~/.ssh/config`:

```sshconfig theme={null}
Host bastion
  HostName jumphost.example.com
  User user

Host target
  HostName 10.0.0.10
  User user
  ProxyJump bastion
```

Then connect with:

```bash theme={null}
ssh target
```

## Notes

* If you also need port forwarding, see the Port forwarding guide.
* If your connection is unstable, Undying Terminal's session persistence helps you avoid losing long-running commands when the underlying SSH transport drops.