> At the cost of some resources belonging to the people sending the > mail. Anecdotal evidence goes back at least to the late '80s, when > WSMR-SIMTEL20.ARMY.MIL sometimes had nontrivial backlogs in its > outbound mail queue due to all the delays associated with trying all > those MX relays at sites that did this. Yes, the mail got through > eventually, and yes, we've learned how to MTAs that are less sensitive > to this kind of problem, but since the situation would have been > completely avoidable if the zone admins hadn't listed all those > unreachable addresses, it's hard to avoid viewing it as (presumably > unwitting) anti-social behavior that's worth discouraging. > > Completely gratuitous externalities considered harmful.
motto of poor dns admin: think locally, act globally randy
