I have found that some UAs (e.g Grandstream's ones) send the Proxy-Authorization header even in ACKs messages.
As we don't explicitly try to authenticate ACKs, we cannot use the consume_credentials() function. In fact, it seems that we have to call proxy_authorize() before we can use the consume_credentials(). But it's contrary to RFC to call proxy_authorize() for ACKs and CANCELs methods!
So, how can we prevent the Proxy-Authorization information to be forwarded to subsequent hops?
Thanks.