Introduction to Undying Terminal

Persistent SSH sessions on Windows that survive network interruptions

Welcome to Undying Terminal

Undying Terminal is a Windows-native persistent terminal solution that keeps your SSH sessions alive through network disconnects, VPN switches, laptop sleep, and other interruptions that would normally kill your terminal session.

The Problem We Solve

Traditional SSH sessions are fragile. They break when:

• Your network connection drops
• Your laptop goes to sleep
• You switch VPN connections
• You change WiFi networks
• Your connection times out

Result: Lost work, interrupted processes, and frustration.

The Undying Terminal Solution

Undying Terminal implements a client-server-terminal architecture with:

Automatic Reconnection

Detects disconnects and reconnects seamlessly with exponential backoff

Session Recovery

Sequence-based protocol recovers missed packets (up to 64MB buffer)

End-to-End Encryption

Optional XSalsa20 encryption via libsodium for secure communication

SSH Bootstrap

Start remote terminals over SSH, then maintain them over TCP

Key Features

Persistent Sessions

Your terminal stays alive even when:

• Network disconnects occur
• Laptop sleeps/wakes
• VPN switches happen
• WiFi changes

Port Forwarding

Forward Tunnels

# Local 8080 → Remote 9090
./undying-terminal.exe --connect 127.0.0.1 2022 <id> -t 8080:9090

Jumphost Support

Connect through intermediate jump servers:

Keepalive & Recovery

• Automatic heartbeat packets (default 5s)
• Detects dead connections (3 missed → reconnect)
• Sequence-based recovery (resends missed packets)

Architecture

Undying Terminal consists of three components:

1. Server

   undying-terminal-server.exe

   Central session manager listening on TCP (default port 2022). Maintains client registry and handles authentication.

2. Terminal

   undying-terminal-terminal.exe

   ConPTY-based terminal that spawns shell processes and connects to the server via named pipe.

3. Client

   undying-terminal.exe

   User-facing client that handles I/O, reconnection, tunnels, and SSH bootstrap.

Use Cases

Remote Development

Keep long-running build processes alive even when your network drops. Perfect for remote development workflows where interruptions are costly.

System Administration

Maintain persistent connections to remote servers during system updates, backups, or maintenance tasks that take hours.

Mobile/Unstable Networks

Work from coffee shops, trains, or mobile hotspots without losing your terminal sessions when switching networks.

Laptop Users

Close your laptop lid mid-session without losing your work. Sessions survive sleep/wake cycles.

Platform Support

Platform	Status	Notes
Windows 10+	Fully Supported	Primary target platform
Windows Server 2019+	Fully Supported	Service mode available

Undying Terminal is Windows-only.

Performance Characteristics

Metric	Value	Notes
Recovery Buffer	64MB	Packets stored for catchup
Keepalive Interval	5s (configurable)	Heartbeat frequency
Reconnect Backoff	100ms → 2000ms	Exponential backoff
Missed Heartbeats	3 before disconnect	Configurable threshold

Next Steps

Quick Start

Get up and running in 5 minutes

Installation Guide

Detailed installation instructions

Architecture Deep Dive

Understand how it works under the hood

Configuration

Configure server and client options