# UNIX and Linux Sessions over SSH and Telnet | WND Software Docs

Source: https://wndsoftware.com/docs/vt-sessions

### UNIX and Linux sessions (SSH and Telnet)

WND Terminal connects to UNIX, Linux and OpenVMS hosts, and other systems that expect a DEC VT terminal, next to its mainframe and IBM i sessions.

Choose UNIX / Linux (SSH)  or VT (Telnet)  as the host type on the connect page and type the host. WND Terminal is a VT100, VT220 and VT320 terminal with xterm colors and the mouse. It signs in with your ssh-agent, a key file or a password, and checks the host’s key before anything is sent.

On a small screen, swipe the table to read all columns.


| Item | Detail |
| --- | --- |
| Host types | UNIX / Linux (SSH) , encrypted, on port 22 unless the host uses another. VT (Telnet) , not encrypted, on port 23, for older systems without SSH. |
| Terminal | VT100, VT220 and VT320, with the xterm additions programs use today. It tells the host it is xterm with 256 colors unless you choose xterm, VT220, VT320, VT100 or the Linux console. |
| Characters | UTF-8 (the default), ISO 8859-1 (Latin-1) or DEC Multinational |
| Scrollback | 5,000 lines |
| SSH sign-in | Your ssh-agent, a key file in OpenSSH or PuTTY (`.ppk`) format, your usual keys, the host’s own questions, or a password |
| Where it runs | The desktop app on Windows, Mac and Linux, and WND Terminal in a browser |

These sessions sit in the same tabs and split panes as mainframe and IBM i sessions. Themes, macros, the automation API, the audit log, session recording and IT’s policy all work with them.


### Connect to a host

- On the connect page, choose UNIX / Linux (SSH)  or VT (Telnet)  as the host type.
- Type the host name or address.
- Fill in any of the settings below, or leave them as they are.
- Tick Save for next time  to keep the connection in your list.

On a small screen, swipe the table to read all columns.


| Setting | What it does |
| --- | --- |
| User name | The user name to sign in as. Left empty, WND Terminal asks when it connects. |
| Terminal | What WND Terminal tells the host it is (TERM). xterm with 256 colors suits Linux and most UNIX hosts. Choose VT220 or VT100 for OpenVMS and older systems. |
| Characters | UTF-8, or Latin-1 and DEC Multinational for hosts that send 8-bit characters. |
| Backspace | DEL (the Linux default) or Ctrl+H for some older UNIX systems. Ctrl+Backspace sends the other one. |
| Key file | A private key to sign in with, in OpenSSH or PuTTY format. Desktop app only. |
| Proxy | A SOCKS or HTTP proxy, as for any other connection. See [Proxy servers](https://wndsoftware.com/docs/proxy-servers). |

Passwords and key passphrases are never saved. From a shortcut or the command line:


```text
wnd-terminal --connect "Build server=ssh:alice@build.example.com"
wnd-terminal --connect "ssh:alice@build.example.com:2222"
wnd-terminal --connect "telnet:vms.example.com"
```


### Signing in

Over SSH, WND Terminal tries these in order.

- Your ssh-agent. On Windows that’s the Windows OpenSSH agent or Pageant.
- The key file chosen for the connection.
- Your usual keys in `~/.ssh` (`id_ed25519`, `id_ecdsa`, `id_rsa`).
- The host’s own questions, then a password.

When the host wants a password, or a key file needs its passphrase, WND Terminal asks in the terminal itself. What you type isn’t shown or saved, and it’s wiped from memory once it’s sent. Over Telnet, the host shows its own login prompts, as on any terminal.


### Host keys

The first time you connect to an SSH host, WND Terminal shows the host’s key fingerprint and asks whether to trust it. Check it with the host’s administrator, who can read it on the host with `ssh-keygen -lf`. A trusted key goes in your own list of known hosts.

If a host’s key changes later, WND Terminal refuses to connect and shows both fingerprints. A changed key can mean someone is in the middle of the connection, so ask the host’s administrator before you do anything else. If the key really was replaced, remove the host’s line from `known_hosts` in WND Terminal’s data folder and connect again.

Keys you already trust in OpenSSH (`~/.ssh/known_hosts` and the system’s `ssh_known_hosts`) count too, with hashed names, wildcards and `@revoked` lines. SFTP in the [file transfer client](https://wndsoftware.com/docs/file-transfer) uses the same list, so a host trusted in one is trusted in the other. IT can list the keys it trusts and stop people trusting others.


### The terminal

- 16 colors from the theme, 256 colors and true color, with bold, dim, italic, underline, blink, reverse and strike-through.
- Full-screen programs such as `top`, `vi`, `less`, `htop` and `mc`, with scroll regions and the DEC line-drawing characters.
- The mouse for programs that ask for it. Hold Shift to select text instead.
- Bracketed paste, so a shell knows pasted text wasn’t typed.
- The window title the host sets, shown on the tab.
- 80 and 132 columns for programs that switch, and any other size.

The session fits the window. Resize it, split it or change the text size and the host is told the new rows and columns, so programs redraw. Lines that scroll off the top are kept. Scroll back with the mouse wheel or Shift+Page Up, and Copy everything (with the scrollback)  on the right-click menu copies all of it.


### Keys

On a small screen, swipe the table to read all columns.


| Key | Sends |
| --- | --- |
| F1 to F4 | PF1 to PF4, as on a VT keyboard |
| F5 to F12 | F5 to F12 |
| Shift+F1 to Shift+F10 | F11 to F20 on VT220 and VT320 (F15 is Help, F16 is Do) |
| Numeric keypad | Digits, or the VT keypad’s codes when the program asks for them |
| Ctrl+letter | The control character, such as Ctrl+C or Ctrl+D |
| Alt+key (Option on a Mac) | Escape, then the key, for Emacs and shells |
| Ctrl+Shift+C, Ctrl+Shift+V | Copy and paste (⌘C and ⌘V on a Mac) |

Ctrl+C, Ctrl+V and the other Ctrl keys go to the host, as they do in any terminal.


### Macros, scripts and recordings

[WND Terminal macros](https://wndsoftware.com/docs/macros) type, press keys and wait for text here as in the other sessions. `press` takes VT keys by name, such as `press F5`, `press Ctrl+C` or `press KPEnter`. A UNIX host doesn’t say when it has finished, so wait for what it shows, such as `wait "$ "`. A password typed at a password prompt is recorded as `{password}`, never itself.

The [automation API](https://wndsoftware.com/docs/automation-api) reads these screens and types into them the same way. Session recording, when IT turns it on, records each screen and each command line. Input at a password prompt is recorded only as “typed at a password prompt”. Card numbers and your masking patterns are hidden on the screen, in copies, in recordings and in anything sent to the AI. The audit log has each connection with its host type, and any SSH host key that was refused, with its fingerprint.


### Bring sessions over from PuTTY and other emulators

Drag the files onto the window, or use Import…  on the connect page.

- PuTTY.  Export the saved sessions from the registry with `reg export HKCU\Software\SimonTatham\PuTTY\Sessions putty.reg` and drop the `.reg` file. SSH and Telnet sessions come across with host, port, user name, terminal type, key file and window size.
- Reflection.  VT session documents (`.rdox`) from Reflection Desktop and Reflection Workspace.
- BlueZone.  VT sessions (`.zvt`).
- Others.  The VT sessions of HostExplorer, PowerTerm, Extra!, PASSPORT and IBM i Access Client Solutions.

The [Migration readiness report](https://wndsoftware.com/migration-readiness-report) counts these sessions as imported.


### Other text terminal models

The desktop app also offers [VT52](https://wndsoftware.com/vt-terminal-emulator#vt52) and [VT102](https://wndsoftware.com/vt-terminal-emulator#vt102), plus explicitly partial [VT420](https://wndsoftware.com/vt-terminal-emulator#vt420) and [VT520](https://wndsoftware.com/vt-terminal-emulator#vt520) profiles over Telnet. These profiles identify themselves to the host and implement the specific controls described on each model page. For PC-style and UNIX console applications, see [BBS ANSI with DOS CP437](https://wndsoftware.com/bbs-ansi-terminal-emulator), [SCO ANSI](https://wndsoftware.com/sco-ansi-terminal-emulator) and the [partial AT386](https://wndsoftware.com/at386-terminal-emulator) profile. The [software-host lab](https://wndsoftware.com/downloads/wnd-model-samples.zip) opens a visible sample for each one. Check your application in a proof of value; these later profiles have not been separately validated through the browser gateway.


### In a browser

UNIX and Linux sessions work in [WND Terminal in a browser](https://wndsoftware.com/browser) too. There, people sign in with a password or the host’s questions. The gateway never uses SSH keys or an agent of its own for them.


### IT settings

On a small screen, swipe the table to read all columns.


| Setting | Group Policy name | What it does |
| --- | --- | --- |
| `AllowSSH` | UNIX and Linux sessions | False turns off SSH sessions. |
| `AllowTelnetVT` | UNIX and Linux sessions | False turns off Telnet sessions. `RequireEncryption` turns them off too. |
| `AllowNewHostKeys` | UNIX and Linux sessions | False stops people trusting a new host key themselves, here or with SFTP. |
| `VTAllowedHosts` | UNIX and Linux hosts people may connect to | The hosts people may reach, such as `*.unix.bank.example`, `10.20.*` or `build.bank.example:2222`. |
| `SSHKnownHosts` | SSH host keys your organization trusts | Host keys as OpenSSH `known_hosts` lines. A host listed here is accepted only with one of its listed keys. |
| `Connections` | Mainframe connections | Your own UNIX and Linux connections, with `"HostType": "ssh"` or `"telnet"` and `SignOnUser` for the user name. As a line: `Billing server\|billing.bank.example\|22\|ssh\|user=billing`. |

`AllowCopy`, `AllowPaste`, `MaskCardNumbers`, `MaskPatterns`, `AllowAutomation`, `RecordSessions`, `AllowOtherHosts`, `Proxy` and `LockHostType` apply to these sessions as to the others. See the [policy settings reference](https://wndsoftware.com/docs/policy-settings).


### What works differently

- Lines aren’t re-wrapped when the window gets narrower. The host redraws them.
- Accents typed as separate combining characters aren’t shown. Accented letters themselves are.
- Double-width and double-height lines show at normal size.
- Session recordings keep the 16 theme colors, and the nearest of them for 256-color and true-color text.


### Related

[File transfer SFTP with the same known hosts list. Read →](https://wndsoftware.com/docs/file-transfer)
[Macros Type, press keys and wait for the prompt. Read →](https://wndsoftware.com/docs/macros)
[Policy settings Every setting IT can lock. Read →](https://wndsoftware.com/docs/policy-settings)

### Questions


#### Can WND Terminal replace PuTTY for our UNIX users?

For terminal sessions, yes. It imports PuTTY saved sessions from a registry export, signs in with the same keys and agent, and checks host keys the same way. The sessions sit next to mainframe and IBM i sessions in the same app.


#### Does it work with OpenVMS?

Yes. Choose VT220 or VT100 as the terminal type for OpenVMS and other older systems, over SSH or Telnet.


#### Are SSH passwords or passphrases saved?

No. They are asked for in the terminal, never shown or saved, and wiped from memory once they are sent.


#### Can IT control which UNIX hosts people reach?

Yes. VTAllowedHosts lists the hosts people may connect to, SSHKnownHosts lists the host keys your organization trusts, and AllowNewHostKeys = false stops people trusting other keys themselves.

Technical reviewer: [Albert Joseph](https://wndsoftware.com/authors/albert-joseph), WND Software.