Generate a new RSA key pair customizing the comment on the public key (that by default is your email):

ssh-keygen -f ~/.ssh/new-key -C "this is the new key comment, which by default is your email"

Creating an alias to connect to a server with a non semantic URL and non default port:

$ vim .ssh/config
# backup server
Host home_server
HostName 666.tcp.ngrok.io
Port 12345

Then, you can connect to this server this way:

$ ssh tiago@home_server