On Fri, 22 Aug 2014, Robert Xiao wrote:

> cURL may erroneously produce this error:
>
>> curl: (33) HTTP server doesn't seem to support byte ranges. Cannot resume.
>
> when asked to continue downloading a file that is already completed. This
> happens with servers that do not send Content-Range headers when replying
> with the HTTP 416 error ("Requested Range Not Satisfiable"), even if the
> server ordinarily supports Content-Range. In particular, when attempting to
> continue a completed download, cURL will request a byte range past the end
> of the file, which triggers a 416 error.

Not a comment on the issue but a further observation: Some caches,
e.g. Varnish, will send a 200 and the entire object in response to
a completely unsatisfyable Range: request rather than a 416. Resuming
with a one-byte overlap with the existing content can help avoid this
unnecessary download.

--
Monty Brandenberg, Software Engineer                               MCB, Inc.
mcbinc_at_panix.com                                             P.O. Box 425292
mcbinc_at_pobox.com                                   Cambridge, MA  02142-0006
617.864.6907
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