william(at)elan.net wrote: > > On Wed, 30 May 2007, Jim Fenton wrote: > >> (3) Upward query vs. wildcard publication. 27 messages in discussion >> from 15 people. Most of the discussion was a rehash of the idea of >> associating semantics with DNS zone-cuts, which we had already >> discussed and rejected. I have also been trying to get an opinion >> from DNSOP on the idea of a one-level upward search (which I think >> solves 90% of the problem), but haven't gotten any response. > > Dont do it. The issue is that you can not properly tell where zone > delegation starts. I know resourceful programmers (including me) > keep track of this data and know that for example ".com" is one > delegation but ".uk" is not and there you have ".co.uk". But the > list is actually rather large and for several ccTLDs you have both > use ".com.??" and ".??" as proper delegation zones. So getting > around this is just way too tricky and if you don't what you end > up doing is sending multitude of extra queries to ccTLD name servers. > This is not proper operational approach as extra load would not be > spread but directed towards several single points on the net. >
The number of upward queries to TLDs and other "non-delegation zones" would be limited by negative cacheing; each verifier should only be making one such query per minimum TTL period. I'm not sure how to assess what would be an "acceptable" load, however, and in any case the min TTL is sometimes rather short (15 minutes for .com, I see) so that might not be enough help. As for Doug's subsequent suggestion of publishing a list of such non-delegation zones somewhere, we would need to normatively refer to such a list, which means that it would need to be maintained by IANA or a similar authority. I don't see that as a likely possibility, especially since the usage of ccTLDs is outside IANA's scope. -Jim _______________________________________________ NOTE WELL: This list operates according to http://mipassoc.org/dkim/ietf-list-rules.html
