Verified on Ubuntu 18.04.

Install mosh on both server and client hosts and coonect it:

sudo apt install mosh  # on both server and client host
mosh yourname@1.2.3.4  # on client host

You could connect to mosh server right after installation with apt, without restarting SSH service or other operations.

Use IPv6 as is: mosh yourname@ed00:caf7:bb2a:feb4:0f99:9e5a:6a0e:ea79.

Mosh can read SSH config defined in ~/.ssh/config. So with the following SSH config on client host:

Host yourserver
Hostname 1.2.3.4
User yourname

Or the IPv6 format:

Host yourserver
Hostname ed00:caf7:bb2a:feb4:0f99:9e5a:6a0e:ea79
User yourname

Now you can connect to server with mosh yourserver.

Multi-hop with Mosh

Mosh hasn't implemented ProxyCommand of SSH yet. So you can only use multi-hop command manually.

ssh + mosh: ssh -A -t x84 mosh tc

ssh + mosh + ssh: ssh -A -t x84 mosh tc ssh algo

You need to define SSH aliases: x84 on you client, tc on x84 host, and algo on tc host, with their ~/.ssh/config respectively. And add pub_key for no_password login.

For convenience, add alias stc='ssh -A -t x84 mosh tc' in startup script. Now you can ssh to tc server simply with stc, and ssh to algo with stc ssh algo.

See note 'Multi-hop SSH' for details about ProxyCommand and manual multi-hop of SSH.