[alexchamberlain]

Custom headers should be prepended with "X-".

Also, the top line should read POST rest/getAuthID.aspx HTTP/1.1

Correction: Use of "X-" has been depreciated in a draft resolution.

Edit: As mentioned below, it isn't compliant in its use of the verbs (GET/POST etc).

[SomeOtherGuy2]

Custom headers do not REQUIRE a prefix. So the lack of prefix does not make it non-compliant. In fact, the HTTP RFC doesn't even say they SHOULD have a prefix. And RFC822 which defines headers only says that protocol mandated headers MUST NOT be prefixed with "X-". Also, there's a draft proposal to deprecate the "X-" header prefix as it does more harm than good: http://tools.ietf.org/html/draft-ietf-appsawg-xdash-02

Second, absolute URIs are perfectly valid, all HTTP/1.1 servers MUST accept them: http://www.w3.org/Protocols/rfc2616/rfc2616-sec5.html#sec5.1