User reported slowdown in the The DHCP parser. It turns out that the DHCP parser did does not register tx detect flag callbacks resulting the callbacks. This prevents transactions on a flow never from being freed. This is particular noticeable on DHCP due cleaned up and leads to the 0.0.0.0->255.255.255.255 address pair that is used for many DHCP requests. First fixed as an app-layer fixup to handle parsers without tx detect flags, such as DHCP that don't need them as they don't register any detection engines. The second fix was to throw a fatal error if a detect engine is registered for an app-layer proto without tx detect flags. This should never happen in production, its more of a check during development. Finally protocols that were missing tx detect flags that needed them were fixed up to use them. parser slowing down.