Presumably much traffic sent to 1.1.1.1 will end up hitting filters, more specifics, or just internal routing well before it hits your DNS servers, hence the problem. It would be interesting for someone to get allocated ranges containing 1.1.1.1 and 1.2.3.4 and do some scamper reachability analysis on these ranges (mjl?), and/or something similar to RIPE's debogon[1] project
http://tr.meta.net.nz/datexplore.php/2010-01-22_15:11_1.1.1.1?openas=,AS9901... As of today, this is what TR sees when tracerouting to 1.1.1.1 from various places around the Internet. The BGP feed I get given has a default route in it[1] which shows it inside TELSTRA-NZTRANSIT-AS, which is obviously wrong, don't blame them for my buggy tools :) Interestingly you can see that a couple of places manage to successfully reach 1.1.1.1 (!). [1]: I'm aware that these are easily filterable in cisco/juniper/whatever, however I'm using my own bgp collector I wrote by hand and haven't gotten to adding that feature yet.