> > And what happens to ".re" relative to ".com" has nothing to do > > with the story. > > .edu versus .com then, or .au versus .com, or anything you > want. There are > millions of organizations that don't issue queries for those > zones either. I am pretty sure that the load caused by ".org" to the root is almost equal to the load of ".com", and that ".edu" is pretty close. I would suspect that .re is . According to www.netsizer.com, there are about 200M entries total in the DNS. The most popular domains are .Net (67M), .Com (42M), .Edu (8.7M), .JP (8.5M). A way to look at the root impact issue is to assume a resolver that starts with an empty cache, and starts putting out queries at random. We will assume that the queries' targets are picked at random from the entire population of hosts; this is not entirely correct, but this is the only assumption we can make with the data at hand. Suppose that the resolver's client make N queries during a standard "time-to-live" interval. The probability to hit the root for a given domain is proportional to the probability that at least one of the N queries hit the specific domain, which is a function of N and of the fraction X of hosts that belong to this particular domain: P(1 hit after N queries)=1 - (1-X)^N I ran the number. They are pretty interesting. I picked here 5 significant domains, and computed the chances that a given resolver asks them once to the root after passing 100 queries (N=100), 1000 queries, 10000 queries: Domain Hosts 100 1000 10000 .com 42M 100.0% 100.0% 100.0% .jp 8.5M 98.7% 100.0% 100.0% .fi 1M 40.2% 99.4% 100.0% .cn 124K 6.0% 46.2% 99.8% .su 22K 1.1% 10.6% 67.2% In short, there is not a lot of difference between the very large domain (.com, .net) and the moderately large (.edu, .jp); even medium size domains such as .fi generate almost as much load if you assume a resolver will issue 1000 queries before the cache expires; with this hypothesis, the load generated by a rather small domain like .cn (there are 40 larger domains) is almnost 1/2 of that of .com! Indeed, if you assume that the caches will be good for 10,000 queries, even the smaller domains, like the obsolete .su, will cause a significant load. -- Christian Huitema