HTTP 206 Partial Content indicates the server is delivering only part of the resource because the client sent a Range header requesting a specific byte range. This is used for resumable downloads, video streaming, and PDF viewers that load pages on demand.
The client requested a specific byte range to resume a download or stream media content.
A PDF viewer or video player is fetching specific portions of the file rather than downloading it entirely.
Check that the response includes a Content-Range header specifying the range delivered and total size.
curl -v -H 'Range: bytes=0-1023' https://example.com/file.zip
Verify the server supports range requests by checking for Accept-Ranges: bytes in a HEAD response.
curl -I https://example.com/file.zip | grep Accept-Ranges
Some CDNs or proxies strip Range headers. Ensure intermediaries preserve them.