Nice trick using a proxied netcat command to forward ssh connections through a server. Was not aware of that, and I spend a lot of time running through a front ssh server, thanks!
with netcat you don't have to use agent forwarding. its better in many cases because you have use different keys for the jump host and the destination host for example.
trusting the jump host by using the same key is not very good security wise, as compromising the jumphost would mean compromising all hosts on the network for all users.
using agent forwarding is equally bad of course.
nc solves that.
Likwise if you use this for scp, it works with nc, but it wont with a double ssh.
