3.5.5 Message Processing Events and Sequencing Rules
The server MUST follow standard message-processing rules in [RFC2616]. In addition:
The server MUST support the GET and HEAD verbs.
The server MUST support HTTP byte-range requests containing a single byte range, as described in section 14.35 of [RFC2616]. The server SHOULD support byte-range requests containing multiple byte ranges.
Successful responses to GET and HEAD requests MUST include the Content-Length header.