Using Eternal Terminal

Since a couple of months I’m working remotely from a laptop using my desktop machine at home via SSH. For more info on that see Remote coding or Why remote coding makes sense to me.

I used to use plain SSH to get a shell but I kept having troubles when there were network errors or network changes. Eternal Terminal offers a simple solution to this problem. From the homepage:

Eternal Terminal (ET) is a remote shell that automatically reconnects without interrupting the session.

Since I’ve started using it years ago it’s been a very useful tool that does it’s best to maintain a solid connection.

How to setup

Server setup on Ubuntu 25.10

This guide install ssh server too. If yours wasn’t already setup I recommend reading my SSH Server guide after.

sudo apt-get install -y openssh-server software-properties-common # prerequisite
sudo add-apt-repository ppa:jgmath2000/et # allow installing from the official repository
sudo apt-get update # update apt sources
sudo apt-get install et # install
sudo systemctl enable ssh # start ssh on boot
sudo systemctl enable et # start et on boot
sudo systemctl --no-pager status ssh # verify that the openssh-server is running
sudo systemctl --no-pager status et # verify that the etserver is running
 
# as this point Eternal Terminal is setup, but I don't want telemetry
sudo sed -i 's/telemetry = true/telemetry = false/' /etc/et.cfg
 
sudo systemctl restart et # apply changes

Client setup on Ubuntu 25.10

sudo apt-get install -y software-properties-common # prerequisite
sudo add-apt-repository ppa:jgmath2000/et # allow installing from the official repository
sudo apt-get update # update apt sources
sudo apt-get install et # install
sudo systemctl disable et # check that the server is running
 
# as this point Eternal Terminal is setup, but I don't want telemetry
sudo sed -i 's/telemetry = true/telemetry = false/' /etc/et.cfg
 
et user@hostname # Eternal terminal is ready to connect to the server

Client setup on Termux

Termux is a free android terminal client that let’s me work from my phone in any situation. Read more about how I use it here: Using Termux

pkg upgrade # update all local packages, optional
 
pkg install et # install the package, refreshes sources automatically
 
# as this point Eternal Terminal is setup, but I don't want telemetry
# the exact file path to the file might change depending on your Android build.
# if this fails you can find the termux path with "which bash"
sed -i 's/telemetry = true/telemetry = false/' /data/data/com.termux/files/usr/etc/et.cfg
 
et user@hostname # Eternal terminal is ready to connect to the server

How to use

You can simply use Eternal Terminal how you’d use plain SSH: et user@hostname.

Important flags

• --forward-ssh-agent: Forward ssh-agent socket. This one is very useful and removes the need to run ssh-add on every connection.
• --macserver: Set when connecting to an macOS server. Sets —terminal-path=/usr/local/bin/etterminal
• --tunnel arg: Array of source:destination ports or srcStart-srcEnd:dstStart-dstEnd (inclusive) port ranges (e.g. 10080:80,10443:443, 10090-10092:8000-8002)

How it works

This article form their website explains it in details: How Eternal Terminal Works

I also made these 2 mermaid graphs to show what’s going on:

Diagrams

Diagram of how SSH behaves on network change

graph TD
    Client[SSH Client]
    
    subgraph "Initial Connection"
        Socket1[TCP Socket<br/>:random → :22]
        Session1[SSH Session]
    end
    
    subgraph "After Network Change"
        Socket2[TCP Socket<br/>:random → :22]
        Session2[Connection Failed<br/>Session Lost ❌]
    end
    
    Server[SSH Server]
    
    Client --> Socket1
    Socket1 --> Session1
    Session1 --> Server
    
    Client -.->|Attempt Reconnect| Socket2
    Socket2 -.->|Timeout/Error| Session2
    Session2 -.->|New Session Required| Server
    
    style Client fill:#e1f5ff
    style Server fill:#ffe1e1
    style Socket1 fill:#fff3cd
    style Socket2 fill:#ffcccc
    style Session1 fill:#d4edda
    style Session2 fill:#f8d7da

Diagram of how Eternal Terminal behaves on network change

graph TD
    Client[ET Client]
    
    subgraph "Initial Connection"
        SSH1[SSH Tunnel<br/>Authentication]
        Socket1[TCP Socket<br/>:random → :2022]
        Session1[Persistent Session]
    end
    
    subgraph "After Network Change"
        SSH2[SSH Tunnel<br/>Re-authentication]
        Socket2[New TCP Socket<br/>:random → :2022]
        Session2[Same Session<br/>Reconnected ✓]
    end
    
    Server[ET Server<br/>etserver]
    
    Client --> SSH1
    SSH1 --> Socket1
    Socket1 --> Session1
    Session1 --> Server
    
    Client -.->|Auto Reconnect| SSH2
    SSH2 -.-> Socket2
    Socket2 -.-> Session2
    Session2 -.-> Server
    
    style Client fill:#e1f5ff
    style Server fill:#ffe1e1
    style SSH1 fill:#e8daff
    style SSH2 fill:#e8daff
    style Socket1 fill:#fff3cd
    style Socket2 fill:#fff3cd
    style Session1 fill:#d4edda
    style Session2 fill:#d4edda