Distributed denial-of-service attacks on root nameservers

Distributed denial-of-service attacks on root nameservers are <a href="/facts/Internet/Xw1rVvJU">Internet</a> events in which distributed <a href="/facts/Denial-of-service_attack/6nkoK02J">denial-of-service attacks</a> target one or more of the thirteen <a href="/facts/Domain_Name_System/rfxdWFsj">Domain Name System</a> <a href="/facts/Root_nameserver/AoQPBB26">root nameserver</a> clusters. The root nameservers are <a href="/facts/Critical_Internet_infrastructure/L3SXSILK">critical infrastructure components of the Internet</a>, mapping <a href="/facts/Domain_name/FDLD2m5G">domain names</a> to <a href="/facts/IP_address/z9V22Sw9">IP addresses</a> and other resource record (RR) data.
Attacks against the root nameservers could, in theory, impact operation of the entire global Domain Name System, and thus all Internet services that use the global DNS, rather than just specific websites. However, in practice, the root nameserver infrastructure is highly resilient and distributed, using both the inherent features of DNS (result caching, retries, and multiple servers for the same zone with fallback if one or more fail), and, in recent years, a combination of <a href="/facts/Anycast/d6lUjbno">anycast</a> and <a href="/facts/Load_balancer/jddk6ang">load balancer</a> techniques used to implement most of the thirteen nominal individual root servers as globally distributed clusters of servers in multiple data centers.
In particular, the caching and redundancy features of DNS mean that it would require a sustained outage of all the major root servers for many days before any serious problems were created for most Internet users, and even then there are still numerous ways in which ISPs could set their systems up during that period to mitigate even a total loss of all root servers for an extended period of time: for example by installing their own copies of the <a href="/facts/DNS_root_zone/pVhV8cWh">global DNS root zone</a> data on nameservers within their network, and redirecting traffic to the root server IP addresses to those servers. Nevertheless, DDoS attacks on the root zone are taken seriously as a risk by the operators of the root nameservers, and they continue to upgrade the capacity and <a href="/facts/DDoS_mitigation/JA463Bul">DDoS mitigation</a> capabilities of their infrastructure to resist any future attacks.
An effective attack against DNS might involve targeting <a href="/facts/Top-level_domain/azjpPu2M">top-level domain</a> servers (such as those servicing the <a href="/facts/.com/zCIIIdYa">.com</a> domain) instead of root name servers. Alternatively, a <a href="/facts/Man-in-the-middle_attack/dx4cojdz">man-in-the-middle attack</a> or <a href="/facts/DNS_spoofing/k85Akwm4">DNS poisoning</a> attack could be used, though they would be more difficult to carry out.

Distributed denial-of-service attacks on root nameservers open-in-new

Distributed denial-of-service attacks on root nameservers