Dears,
maybe it will look like newbie question, but I am trying to find out, wheter marking the connection to be fasttracked by mangle in the prerouting chain means that the connection belonging packets (including the first one) will never be inspected by firewal filter rules of forward or input chain or whether at least the connection opening packet will pass entirely through the firewall (routing and postrouting chains, mangle, nat, filter including) and the fasttrack mark will apply just for the subsequent packets…
Looking at the packet flow diagram https://wiki.mikrotik.com/wiki/Manual:Packet_Flow_v6
and at the fasttrack, mangle or filter manual pages does not giving clear answer to me in this case.