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

# Jupyter & SSH FAQ

> Connecting to instances via Jupyter and SSH

## Jupyter

### What is the HTTPS security warning?

When accessing Jupyter, browsers show a security warning because we use self-signed certificates. To fix:

1. Download and install our [TLS certificate](/guides/instances/jupyter)
2. **Windows/Linux:** Can bypass by clicking Advanced → Proceed
3. **macOS:** Must install certificate in Keychain Access

Installing the certificate removes the warning permanently.

### Why are Jupyter transfers slow?

Jupyter's upload/download is not optimized for large files. Alternatives:

* Use SCP/SFTP for large transfers
* Use cloud storage (S3, GCS)
* Use the Vast CLI copy commands
* Zip multiple files before downloading

### How do I delete files in Jupyter to free space?

Jupyter moves deleted files to trash. To permanently delete:

```bash theme={null}
# In Jupyter terminal
rm -r ~/.local/share/Trash
```

### How do I run Colab notebooks?

1. Select the [PyTorch template](https://cloud.vast.ai/?ref_id=43484\&template_id=e4c5e88bc289f4eecb0c955c4fe7430d) with Jupyter enabled
2. Start your instance
3. Download the Colab notebook as `.ipynb`
4. Upload to Jupyter
5. Install any missing dependencies with `pip install`

For direct Colab connection, see our [Colab guide](/google-colab).

### How do I download multiple files from Jupyter?

**Jupyter Lab:** Shift-click to select multiple files, right-click to download

**Jupyter Notebook:** Must download individually or zip first:

```bash theme={null}
# Install zip
apt-get install -y zip

# Zip a directory
zip -r all_files.zip /path/to/files/
```

### Missing library or package errors?

Install dependencies in Jupyter terminal:

```bash theme={null}
# System packages
apt-get install -y PACKAGE_NAME

# Python packages  
pip install PACKAGE_NAME
```

## SSH Access

### How do I connect via SSH on Linux/Mac?

1. Generate an SSH keypair:

```bash theme={null}
ssh-keygen -t rsa
```

2. Load the key and verify:

```bash theme={null}
ssh-add
ssh-add -l
```

3. Get your public key:

```bash theme={null}
cat ~/.ssh/id_rsa.pub
```

4. Copy the **entire output** (including `ssh-rsa` prefix and `user@host` suffix) to your [Keys section](https://cloud.vast.ai/manage-keys/)

Example of complete SSH key:

```
ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAZBAQDdxWwxwN5Lz7ubkMrxM5FCHhVz... bob@velocity
```

### How do I connect via SSH from Windows?

Two options:

1. **Windows Subsystem for Linux (WSL)** - Follow Linux/Mac instructions above
2. **PuTTY** - See our [Windows SSH Guide](/guides/instances/windows-ssh-guide)

Make sure to save the key in SSH RSA-2 format when using PuTTY.

### What is tmux and how do I use it?

We connect you to a tmux session by default for reliability. Common commands:

* **Create new terminal:** `Ctrl+b, c`
* **Switch terminals:** `Ctrl+b, n`
* **Split screen:** `Ctrl+b, %` (vertical) or `Ctrl+b, "` (horizontal)

Search "tmux cheat sheet" for more commands.

### Can I disable tmux?

Not recommended (SSH can be unstable), but if needed, add to your onstart:

```bash theme={null}
touch ~/.no_auto_tmux
```

### SSH asks for a password - what's wrong?

There is no SSH password - Vast.ai uses SSH key authentication only. If SSH asks for a password:

* Your SSH key wasn't added correctly to your account
* You didn't copy the entire public key (must include `ssh-rsa` prefix and `user@host` suffix)
* Your SSH client is misconfigured
* The private key isn't loaded in your SSH agent

Double-check that you copied the complete public key to your Keys section.