It was intended that non-backbone sites may use mail-via=DISTRIBUTE, but this is not recommended unless their various tables are up to date. With DIST2, the source node will decide the exact path to be followed by the files and will enforce it upon the other servers. If it chooses a stupid path, mail distribution will be inefficient and it won't be the backbone's fault. Anyway DIST2 is not yet in use so this is a bit academic. Eric