Excuse the potential noobishness of the question, but I'm, well, a bit of a noob when it comes to this domain architecture lark. If "domain architecture" is even the technical term. Anyway, I digress...
So, I've googled this question , but I can't see the answer I'm looking for (maybe it doesn't exist, who knows!?) The situation is that I host a .com top level domain which does a 301 forward to another site on the net not hosted by me. Can I set up a subdomain that then points somewhere else whether that be on my host itself or just some other site elsewhere on the net?
Essentially, if I set up a subdomain, will it too inherit the web forwarding, and if so, can I directly affect where that subdomain points?
Any answers gratefully appreciated!
Before I try to answer your question, let me be a little fussy :)
First thing first you are confusing and mixing together two different protocols ([DNS] and [HTTP]), actually there is even a dedicated page to the Wikipedia for HTTP 301 responses: http://en.wikipedia.org/wiki/HTTP_301 (but you should read the whole shebang: ([Wikipedia, search for HTTP] is always a good start, and the [RFC 2616] is absolutely a must, IETF RFCs are not easy reading but the Internet is built on them).
DNS is used to translate a name, like www.example.com into an IP address, like 192.168.0.1, in order to locate a machine on the Internet. So DNS is involved as the one of the very first steps a browser takes in order to resolve an URL: but once the "machine name" is translated by the separate DNS Service, and it has become an IP address, DNS job is over and it is used/involved no more.
Then when a browser, using HTTP, contacts the Web Server located on that machine (in this example the machine www.example.com, which the DNS Service has kindly translated to an IP address, in our example 192.168.0.1, because the operating system can only use an IP address as the argument for an [internet socket]) and only at that moment the web server, instead of serving a page, answers whith an "error" code (which, actually is a "response header" with a numeric code that does not start with "2").
Only that this error code is actually used to tell something else: that the browser should try again an "HTTP request", this time connecting to another machine (and, as long as this redirection is "permanent" instead of "temporary" ([HTTP_307]), the new address should be remembered by the browser, its cache and history).
So, if you can setup [redirection response header] on the first machine, it means that there is a Web Server on that first machine that is programmed (given a certain URL pattern) to spit out a Redirection Header, and as long as you can control these redirections, you can as well send the browser wherever you want, not merely sending them to another machine on the Internet but to another URL as well, even on the same website (actually this is the original intended use of code 301, as a measure against [link rot]).
Basically you are free to do whatever you want, or better, to send them wherever you want.
The pros are obvious... the cons are that you must have control over the first web server, and that the visiting browsers will have to perform two "GET request" in order to land at the intended page (this is not grim as it looks, since the [RFC 2616] suggests that the browser (they call it User Agent) caches and remembers the redirection (because it is permanent)).
Disclaimer: I am being prevented to post hyperlinks, but they where basically all from the Wikipedia so, if you will, you can look the words in brackets "[...]" on the Wikipedia...