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 DNS sinkhole A DNS sinkhole, also known as a sinkhole server, Internet sinkhole, or Blackhole DNS is a DNS server that gives out false information, to prevent the use of a domain name. A sinkhole is a DNS provider that supplies systems looking for DNS information with false results, allowing an attacker to redirect a system to a potentially malicious destination. DNS sinkholes have also historically been used for non-malicious purposes. When a computer visits a DNS source to resolve a domain name, the provider will give a result if possible, and if not, it will send the resolution system