Sinkhole urban areas due to water main breaks or sewer collapses when old pipes give way. They can also occur from the overpumping and extraction of groundwater and subsurface fluids. Sinkholes can also form when natural water-drainage patterns are changed and new water-diversion systems are developed. Some sinkholes form when the land surface is changed, such as when industrial and runoff-storage ponds are created; the substantial weight of the new material can trigger a collapse of the roof of an existing void or cavity in the subsurface, resulting in development of a sinkhole. Sinkholes tend to occur in karst landscapes. Karst
DNS sinkhole to a higher-level provider to try again. The higher a DNS Sinkhole is in this chain, the more requests it will receive, and the more impactful it will be. A sinkhole is a standard DNS server that has been configured to hand out non-routable addresses for all domains in the sinkhole, so that every computer that uses it will fail to get access to the real website. The higher up the DNS resolution chain the sinkhole is, the more requests it will block as it will supply answers to a greater number of lower NS servers that in turn will