Can Time Machine do a Non-Direct NAS backup?

Question

I want to be able to use a NAS on my home network.
The biggest thing for me about NAS is the potential to backup to Time Machine using other people's networks.
For example, I'll be in my college, which is a couple cities away from my home network... and I'll want to backup.
Or an even more extreme situation. I plan on travelling to Mexico and will want to backup my homework. Even though my NAS will be in Canada.
I've been told that too do this I'll need to use a FTP.
Yet nobody's seemed to talk about having experience actually doing this.
I know the obvious solution is to carry an external with me wherever I go... but I'd rather just use a NAS.
Please let me know if you find (or have) any cases where you have been able to backup onto a NAS with time machine while you're not on the same network as your NAS.

Answer 1

Be very careful here:  just because a 3rd-party vendor claims to support Time Machine doesn't necessarily mean that Apple supports that configuration, or that it will work reliably in all circumstances (many won't).
Before buying one of these, carefully investigate the following:
•If you’re planning to use the NAS for other data, in addition to your Time Machine backups, be sure you can partition it (or set up separate "shares" or "accounts" via the NAS, since you can’t with Apple’s Disk Utility), or somehow limit the amount of space the backups can use.  Otherwise the backups will, eventually,  use all the available empty space, possibly leading to conflicts.  See  question #3  for details.
•Look at the setup instructions.  If there’s any mention of a Terminal command involving "unsupported devices," or installation of drivers or kernel extensions to fool Time Machine into thinking it’s a locally-connected drive, use caution.  These may prevent you from doing a full system restore to a new or replaced internal hard drive.  This is because OSX doesn’t do a full system restore;  it’s done by booting up from your Recovery HD (Lion and later) or OSX Install disc (Snow Leopard or Leopard) and using the the Installer utility on it.  That utility won’t have those additions, and you can't add them to it;  thus it may not be able to connect to your backups when you need them the most.  (See question #14 for details on doing a full restore.)
•Consider whether the maker is reputable and likely to continue supporting the NAS for as long as you'll be using it.  If Apple changes requirements, will the maker update the NAS so it will work with the new version of OSX?  Many that worked on Snow Leopard didn't work on Lion without such updates.  A few weren't updated for quite a while, and some never were.
For more on this go to http://pondini.org/TM/2.html