Get the door, Jeeves, visitors calling.
If you need ways to connect to your system remotely, but in a secure way and only when you want it to be available, check out Paul Keck’s really creative use of SSH keys. With a cron job using curl or wget, you could create a file on a particular web server that would cause an ssh tunnel (by way of that cron job) to be created from the inside of your system. That tunnel would listen on a port on the remote end, which you can then use to ssh in. Really handy sometimes. (Assuming my description is clear enough that if you have experience with this stuff you know what I mean, of course.)