Hi. I have following scenario in which I currently face a problem with Undertow: I use Undertow as a Reverse-Proxy (via SimpleProxyClientProvider). I want to enable a Signature-based authentication where the client can sign the HTTP request with its private key and the Reverse-Proxy (implemented with Undertow) can check with the client's public key if it was signed correctly. I do not only want to include HTTP headers (Host, Date, ..) and Method/Path, but also the request body. For that I need to consume the HttpServerExchange's InputStream: if (isHttpMethodWithBody(method)) { exchange.startBlocking(); final String body = new Scanner(exchange.getInputStream(), "UTF-8").useDelimiter("\\A").next(); .. Unfortunately in this scenario, the Exchange's "getRequestChannel()" returns null as "another party already acquired the channel". I found "Connectors.resetRequestChannel(exchange)"; But just calling this results after the InputStream was consumed results in a "IOException : UT001000: Connection closed". Is there any way to "consume" the request's payload, but afterwards simply forward to the proxy target? Any help is really appreciated, Thanks! -- Thomas Jäckle