Allowing users to point their domains to a web-based application?

Question

I'm possibly developing a web-based application that allows users to create individual pages. I would like users to be able to use their own domains/sub-domains to access the pages.

So far I've considered:

A) Getting users to forward with masking to their pages. Probably the most in-efficient option, as having used this before myself I'm pretty sure it iFrames the page (not entirely sure though).

B) Having the users download certain files, which then make calls to the server for information for their specific account settings via a user key of some sort. The most efficient in my mind at the moment, however, this requires letting users see a fair degree of source code, something I'd rather not do if possible

C) Getting the users to add a C-NAME record to their DNS settings, which is semi in-efficient (most of these users will be used to uploading files via FTP hence why B is the most efficient option), but at the same time means no source code will be seen by them.

The downside is, I have no idea how to implement C or what would be needed.

I got the idea from: http://unbounce.com/features/custom-urls/.

I'm wondering what method of the three I should use to allow custom urls for users, I would prefer to do C, but I have no idea how to implement it (I'm kind of asking how), and whether or not the time spent learning how-to/getting that kind of functionality set-up would even be worth it.

Any answers/opinions/comments would be very much appreciated :)!

Answer 1

Option C is called wildcard DNS: I've linked to a writeup that gives an example of how to do it using Apache. Other web server setups should be able to do this as well: for what you want it is well worth it.