Serial Console (Serial-over-SSH)

ZestSSH supports serial console access via SSH-based console servers (also known as terminal servers or console concentrators). This is the standard method used by network engineers to access the serial console ports on routers, switches, firewalls, and other equipment remotely.

Availability

Platform	Status
Android	Full support
iOS	Full support
Windows	Full support
macOS	Full support
Linux	Full support

How It Works

ZestSSH does not connect directly to a physical serial port. Instead, it connects to a console server appliance via SSH. The console server bridges the SSH session to a physical serial port attached to the target device. Traffic between ZestSSH and the console server is fully encrypted via SSH.

Common console server appliances and their typical port mappings:

Vendor	Model Examples	Base Port	Serial Port 1	Serial Port 5
Opengear	CM7100, OM2200	3000	3001	3005
Digi	Passport, Connect	7000	7001	7005
Avocent	ACS 6000/8000	3000	3001	3005
Lantronix	SLC	10001	10001	10005
Generic	Various	2000	2001	2005

Device Presets

ZestSSH includes serial configuration presets for common network equipment:

Preset	Baud Rate	Config	Flow Control
Cisco IOS	9600	8N1	None
Juniper JUNOS	9600	8N1	None
MikroTik RouterOS	115200	8N1	None
Arista EOS	9600	8N1	None
HP/Aruba ProCurve	9600	8N1	XON/XOFF

The serial parameters (baud rate, data bits, parity, stop bits) are metadata in ZestSSH — the actual serial configuration is set on the console server itself. Custom baud rates from 300 to 921600 are supported.

Quick Start

1. Create a new connection and select Serial as the protocol.
2. Enter the console server hostname or IP.
3. Set the port to match the serial port mapping on your console server (e.g., 3001 for serial port 1 on an Opengear).
4. Select or create an SSH identity for the console server.
5. Optionally select a device preset matching your target equipment.
6. Tap Connect.

Features

• Break signal — Send a serial break signal (useful for Cisco password recovery and similar operations). ZestSSH sends an ESC-B sequence that most console servers translate to a physical serial break.
• Full SSH encryption — All traffic between ZestSSH and the console server is encrypted. The serial link between the console server and the device is physical and not subject to network interception.
• Standard SSH auth — Supports the same authentication methods as regular SSH connections (password, public key, keyboard-interactive).

Limitations

• No direct USB serial — ZestSSH does not currently support connecting directly to USB serial adapters (e.g., USB-to-RS232 cables). Direct USB serial would require the flutter_libserialport package, which is planned but not yet integrated. Use serial-over-SSH through a console server instead.
• Console server required — A network-accessible console server appliance must be connected to the target device’s serial port.
• Serial parameters are display-only — The baud rate, parity, and flow control settings in ZestSSH are for reference. The actual serial parameters must be configured on the console server to match the target device.

Troubleshooting

Cannot connect to console server

• Verify SSH connectivity to the console server host and port.
• Confirm the port number matches the serial port mapping for your console server vendor.
• Check that your credentials are valid for the console server.

Connected but no output from device

• The target device may need a carriage return to display a prompt. Press Enter.
• Verify the console server’s serial parameters match the target device (baud rate, data bits, parity, stop bits).
• Check that the physical serial cable is connected and the target device is powered on.

FAQ

Q: Can I connect a USB serial adapter directly to my phone or computer? A: Not currently. Direct USB serial support is planned for a future release. For now, use a console server with SSH access.

Q: What is 8N1? A: 8N1 means 8 data bits, No parity, 1 stop bit. This is the most common serial configuration for modern network equipment.