I forget how many times resolvers retry failed UDP DNS lookups, but I
think it is something like 3 or 4. So, by timing out, they are
actually increasing their load.
Personally, I still suspect that the real problem is a broken DNS
proxy. I suspect that someone somewhere gave the "this saves
bandwidth on an expensive link" as an excuse, and in that situation,
the excuse works very well to get people to stop complaining.
I suspect the "broken" proxy is actually an intentional filter applied
at the input end of trans-oceanic links.
While I'm not privy to the filtering details, I do know the operators
of some such links go to considerable effort to reduce unnecessary
traffic.
Certainly if I were running an African ISP, I'd be doing my spam and
virus filtering before the traffic crossed to Africa, and I'd be
weeding out any other traffic not necessary enough for my third-world
users to be paying for.
--
Dick St.Peters, stpeters(_at_)NetHeaven(_dot_)com
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