Duane Wessels wrote:
The IN-ADDR.ARPA delegations for RFC1918 space are just like any other block. You'll just end up hitting IANA's blackhole servers, and not all that much, the cache times are one week.
In theory, yes.
In reality there are quite a few resolvers that, apparently, do not receive the delegation response and continue to hit the roots with PTR queries for RFC1918 space.
Is there something special about RFC1918 in this respect? Wouldn't these resolvers not work for all of the IN-ADDR.ARPA space? Wouldn't they be hitting the roots with all kinds of PTR queries?
Recent measurements at a single instance of an anycasted root server show that at least 250 such resolvers generate between 60-120 RFC1918 PTR queries/sec.
I assume (and no idea really if it is a good assumption or not) that the bulk of these broken resolvers do not belong to ISPs. The original recipient said specficially that he was using his ISP's nameservers. If he has broken resolvers, but the ISP servers are sane, he'll obviously end up pounding the ISP servers and perhaps the IANA blackhole servers if the queries are unique, but not the root servers. But yes there are plenty of broken resolvers out there. One of my current favorites is something in Novell print services that likes to do A queries on a single printer name several dozen times per second, wait a few seconds or minutes, then do a query storm on another printer name. These account for over 90% of the queries on some internal DNS servers. -- Crist J. Clark crist.clark@globalstar.com Globalstar Communications (408) 933-4387