Resolving HTTP Error 416 Requested Range not satisfiable (IIS 7.5 example)

The chaos called HTTP often surprises us with some new sweet little error that put us in not so satisfiable position. For example the anonymous HTTP error 416.

This error is product of mismatch between the client (for example browser) and the server regarding to the Accept-Ranges header tag. In particular this error emerges when the client is requesting a bigger resource similar to pdf files or images and awaits for the response of the server. The initial response could be fine but the streaming of the resource could fail. Why?

Accept-Ranges: bytes means that the request can be served partially. After the initial content-length parameter the server should provides us Content-Range tag (bytes size) in the response with every ‘partial’ request to keep the consistency of the stream. If this doesn’t work right, say hello to error 416. To be noted that this is highly influenced by how the client is implemented, not only the server.

To check if the server supports range header we could do a thing. Send HEAD request instead of GET to the wanted resource. If response 206 is returned range is supported. If the response code is 200 server side should change Accept-Range header to not foul clients.

Curl example: $ curl -i -X HEAD http://address/path/resource

Nevertheless let’s just solve the problem. Usually I notice this error in relation IIS -> Chrome or Apache -> Chrome. But it occurs on Firefox too.

Setting Accept-Bytes: none in IIS: Intenet Information Service (IIS) Manager -> Server Node -> Sites -> Problematic Site -> HTTP Response Headers (In IIS section) -> Add (Action) -> Name: Accept-Bytes; Value: none .

Setting Accept-Bytes: none in Apache2 : Enable apache2 mod_headers. Add “Header set Accept-Ranges none” in configuration of host.

Restart changes to take effect.

Have a nice day : )