SSH-Snake can automatically reveal the relationship between systems which are connected via SSH, which would normally take a tremendous amount of time and effort to perform manually.

SSH can use a variety of authentication methods, such as passwords and key pairs. Less common, and not particularly user friendly, are methods like OPIE. The latter is available per default in FreeBSD (and a few other BSDs I believe), but I can't recall a single case where I've seen it being used in the wild. Other implementations, like Google Authenticator make MFA easy to integrate and use, without being too disruptive for the user.

arecord -f cd | ssh -C user@host aplay -f cd

or the other way around

ssh -C user@host arecord -f cd | aplay -f cd

How ssh connection are established

rsync --partial -t -h -z -r --progress -e "ssh" "edgar:/home/deluge/*" .

Make a bridge through the gate
ssh -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -L 1234:opensuse:22 login_x@ssh.epitech.net -N -f

Use it like this:
scp -P 1234 login_x@127.0.0.1:/home/login_x/* ./
or to access any other server inside using opensuse as a gate:
ssh server -o "ProxyCommand ssh -q -p 1234 login_x@127.0.0.1 nc -q0 %h 22"

Direct tunnel to access a ressource inside epitech's network
ssh -4 -At login_x@ssh.epitech.eu -L 4242:localhost:4242 ssh -At -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no opensuse-3 -L 4242:10.10.254.252:4242