How to SSH in to a restricted server using another server by single command

We know that we can ssh in to a server using simple SSH commands and SSH in to any number of different servers using the same command over and over. But sometimes it is useful to know that you can use a single command to do that, so the your middleman will not bother asking you to ssh again. You can do file transfers or downloads the same way.

The problem really occurred to me the time we had a client who had a staging server with IP restricted so every time I connect I had to ask them to add my IP to their firewall since I have a dynamic IP assigned when router restart, that sucks. So I wanted a better approach so I sent them our dev server IP so he can add the IP to their Firewall and I can access their server via our dev sever using the following single command.

Here is the command to use to tunnel through another server:

ssh -t [email protected] ssh userna[email protected]