ip access control vs x-forwarded-for: two java footguns— jetty's InetAccessHandler and undertow's ProxyPeerAddressHandler both let an ip allow-list be driven by the client-supplied X-Forwarded-For header in their documented reverse-proxy setups. the interactions are public and arguably intentional; the real defects are a false jetty javadoc guarantee and a misleading undertow method name, not new bypasses.