> Q: What if all root name serves would stop answering queries?
> A: Now you are stretching it. How likely is that? The diversity in the system will prevent that from happening. But let's treat it as a hypothetical case: In that hypothetical case the Internet will not suddenly grind to a halt. If absolutely nothing is done to correct the situation every hour about 2% of all queries will not be answered, 2% at the end of the first hour, 4% at the end of the second hour and so forth until 48h after the root name servers stop answering queries no DNS names can be resolved anymore. However it is even more hypothetical to assume that nothing will be done to correct this hypothetical situation.
> Even in the hypothetically hypothetical case that the root name server operators would do nothing to correct the situation, the IANA, TLD operators, ISPs and others would have the motivation and the means to take corrective action.
> Again: this is very hypothetical. DNS failures outside the root name servers are much more likely. Name service for the vast majority of top-level domains is very much less redundant than that of the root name servers. Whole top-level domains and major corporations have been unreachable for significant amounts of time because of DNS failures. Name service for the root zone has always been available.
> A: Now you are stretching it. How likely is that? The diversity in the system will prevent that from happening. But let's treat it as a hypothetical case: In that hypothetical case the Internet will not suddenly grind to a halt. If absolutely nothing is done to correct the situation every hour about 2% of all queries will not be answered, 2% at the end of the first hour, 4% at the end of the second hour and so forth until 48h after the root name servers stop answering queries no DNS names can be resolved anymore. However it is even more hypothetical to assume that nothing will be done to correct this hypothetical situation.
> Even in the hypothetically hypothetical case that the root name server operators would do nothing to correct the situation, the IANA, TLD operators, ISPs and others would have the motivation and the means to take corrective action.
> Again: this is very hypothetical. DNS failures outside the root name servers are much more likely. Name service for the vast majority of top-level domains is very much less redundant than that of the root name servers. Whole top-level domains and major corporations have been unreachable for significant amounts of time because of DNS failures. Name service for the root zone has always been available.
http://www.isoc.org/briefings/020/