Reverse proxy of 100-continue aware backend, sends 100 continue even when backend does not. This causes a client to think it should write a request body, while the backend may still respond with a 400 and not read the request body. mod_proxy_http then responds with 502 as a result of AH01097: pass request body failed The backend is doing the right thing: it did not send a 100 continue so it should not be required to read a request body, regardless of transfer encoding or content-length. Expected: mod_proxy_http reverse proxy should not send 100-continue to a client unless the backend does.
Created attachment 34438 [details] in the reverse proxy case, if request had Expects: 100-continue, delay writing 100 continue response until backend has sent 100-continue response
Created attachment 34451 [details] Forward 100-continue (and minimize race when reusing backend connections) I proposed this patch a while ago on the dev@ list ([1]), this is an update for latest trunk, with more (though incomplete) testing. Could you please give it a try? [1]. https://lists.apache.org/thread.html/4e541e032b8a77ebec8248534637b47cdcd4f38af79baa5259845db0@1430360070@%3Cdev.httpd.apache.org%3E
*** Bug 55433 has been marked as a duplicate of this bug. ***
Yann, I tried that patch, but I still get 503 error when expecting a 100 Continue response.