Prevent Istio Proxy from adding Headers


how do I prevent the Istio proxy manipulating certain headers? Envoy is injecting a Content-Length header which breaks communication between our web and app tier for empty responses.

(Fixing in web tier would be my preferred solution, but compatibility requirements…)


Can you provide more context? Envoy inserts content length 0 for empty request bodies. I raised this issue in the upstream envoy, but it was not deemed as critical by envoy maintainers, so left as is. Depending on the conditions, istio filters may or may not be able to manipulate headers within envoy.


Feel free to provide more details here if it is relevant.

Thanks for your response!

I added a comment to the issue you provided and verified it is a strange behavior of envoy.

The problem is, that envoy injects a content length header (with content length 0) to 204 responses which is invalid in HTTP/1.1.