2017-12-07

The Advent of Void: Day 7: mosh

Accessing a remote server over an unstable or high latency connection … can be … a tedious CONNECTION TIMEOUT … RECONNECT task.

mosh(1) stands for MObile SHell and provides a reliable command line connection that outlives network outages and roaming between different networks.

The usage of mosh is pretty easy. On un-firewalled hosts just make sure the remote server runs an sshd(8) deamon and has mosh installed. Then connecting to the server is as easy as:

# mosh username@server

The initial handshake is done through an SSH connection. Once the UDP connection is prepared, the SSH connection is closed. The exact protocol design is described in the mosh research paper

On firewalled systems you need to make sure that the UDP ports between 60000 and 61000 are not filtered as mosh uses a random port in this range.

Once the connection is established feel free to disconnect you rig from the network, change IP addresses, move to another wifi, etc. You’ll see that mosh automaticly reconnects and updates the state of the terminal as long as the used UPD-Port is available.

Find more information about mosh on its homepage.