The Accept-Ranges response-header field allows the server to indicate its acceptance of range requests for a resource.
Origin servers that accept byte-range requests MAY send Accept-Ranges: bytes but are not required to do so. Clients MAY generate byte-range requests without having received this header for the resource involved.
Servers that do not accept any kind of range request for a resource MAY send Accept-Ranges: none to advise the client not to attempt a range request.