Compared to et and mosh

Compared to et and mosh

The original Eternal Terminal (et)

Eternal Terminal by Jason (Jez) Gao and contributors is the direct inspiration for etr. ET solved the reconnecting shell problem elegantly and has been widely used in production for years. etr exists because:

• The original ET is written in C++ with a complex build system; etr is a single cargo install
• ET requires a pre-running daemon (etserver) on the server; etr starts the server on the fly like mosh
• etr uses QUIC (TLS 1.3) as the transport — no custom crypto, reliable ordered delivery, and multiplexed streams built in
• etr supports port forwarding (-L)
• etr's wire format is documented in PROTOCOL.md

If you need a battle-tested, production-grade reconnecting terminal today, use the original ET. etr is newer and less proven. That said — go give ET a star: https://github.com/MisterTea/EternalTerminal

mosh

mosh is another reconnecting shell that also uses SSH for bootstrap and UDP for the session. Key differences:

	mosh	etr
Protocol model	State sync (roaming cursor)	Ordered stream with replay
Transport	UDP (custom)	QUIC (TLS 1.3)
Crypto	AES-128-OCB	TLS 1.3 (AES-256-GCM / ChaCha20-Poly1305)
Post-quantum	No	Not yet (planned via rustls-post-quantum)
Forward secrecy	No	Yes (TLS 1.3 ephemeral X25519 per connection)
Server process	Per-session (like etr)	Per-session
Scrollback	No (roaming display only)	Yes (stream replay)
Port forwarding	No	Yes (-L/-R TCP and UDP, multi-sender)
Escape sequence	~.	~.
Login shell	Yes	Yes (.zprofile/.zlogin sourced)
Session env vars	SSH_CONNECTION	ETR_CONNECTION, ETR_VERSION, SSH_CONNECTION

mosh's roaming-display model makes it very bandwidth-efficient for interactive use. etr's stream model is simpler to reason about and enables correct scrollback and replay.

Summary

	et	mosh	etr
Language	C++	C++	Rust
Server model	Pre-running daemon	Per-session	Per-session
Crypto	AES-256-GCM	AES-128-OCB	TLS 1.3 (AES-256-GCM / ChaCha20)
Post-quantum	No	No	Planned
Forward secrecy	Yes	No	Yes (TLS 1.3)
Protocol spec	Internal	Published	PROTOCOL.md
Install	Package manager	Package manager	cargo install etr