When you are outside of the internal network, and want to ssh to your computer, you have to know its IP address. Normally, if you don't write this down beforehand, you can't do it.
However, thanks to a system known as Zeroconf, there is a way to look up computer IP address on a network, by name. The ideal way to do this would be to ssh to vickyp, and run avahi-resolve-host-name. However, vickyp doesn't have avahi installed. I thus created a workaround.
http://192.168.100.215:8079/ (use this if you are inside the theory network and blocked)
A hostname can be looked up at the URLs above. (Note: because of the outgoing traffic blocking, you need to use the internal IP address to test.(Please join my quest to get rid of outgoing traffic blocking)). To test from the command line, use avahi-resolve-host-name YOURHOSTNAME.local.
As an example, my computer's name is ramanujan. I go to that page, type in ramanujan in the box, and get this:
Thus, from now on, all you have to do is remember you computer's hostname. If your computer reboots and/or the IP address changes, you can find the new IP address without needing to return to work and writing it down.
Your computer must be set up to make use of this. Most GNU/Linux machines seem to be be set up to do this by default. I have no experience in working with this, so please update this page with information if you have to enable it. The GNU/Linux standard zeroconf implementation is avahi.