If you need to proxy via intermediary servers to access your destination (for example, maybe you’re outside your work network and need to access a client estate that is IP-restricted) you can multi-hop manually, or the following host based config can be added to your ~/.ssh/config:

Host *.target.com  ProxyCommand ssh -q user@work.com nc %h 22

This will then allow you to…

ssh user@server.target.com

…and be transparently proxied via proxy-server.com