Linux
SSH config generator
Create a block for ~/.ssh/config with short name, key, port and jump host.
What does this mean?
In the file ~/.ssh/config you give servers a short name along with all the settings. Instead of typing ssh -p 2222 -i ~/.ssh/sleutel beheer@192.168.1.20 you can just type ssh nas. It also works for scp and rsync.
Your key never leaves your computer. This tool only generates text in your browser. More: the SSH cheat sheet.