How to proxy a connection via SSH and others?

Question

ubuntu

There is a VPS server with ip 1.2.3.4 it has access via SSH 1.2.3.4:22
There is a second VPS with ip 9.8.7.5 it has access via SSH
9.8.7.5:22 3333 (instead of 3333 there can be any other port) I got to the first server 1.2.3.4:22
That is, so that I can connect to the first server via SSH using the IP of the second server so that the first server does not know the connection source

Answer 1

Forward with any software for TCP tunneling ..
socat TCP-LISTEN:3333, TCP:1.2.3.4:22
you can also configure it via iptables (but here it seems the source will not change and the first server will send a direct response)
sysctl net.ipv4.ip_forward=1
iptables -t nat -A PREROUTING -p tcp --dport 3333 -j DNAT --to-destination 1.2.3.4:22
iptables -t nat -A POSTROUTING -j MASQUERADE

Answer 2

https://putty.org.ru/articles/putty-ssh-tunnels.html