DNS stands for "Domain Name System" and is used for managing and operating domain names on the internet. To communicate over the internet (IP networks), it is necessary to specify the IP address of the target destination. However, IP addresses are numerical sequences, which are not easy for humans to memorize. Instead, domain names like "f5.com" are commonly used for access. DNS's role is to associate these domain names with their respective IP addresses. The process of finding an IP address from a domain name is called "forward lookup," while the process of finding a domain name from an IP address is called "reverse lookup." Together, these processes are known as "name resolution."
DNS is made up of numerous DNS servers around the world. No single DNS server contains information about all domains. Instead, DNS uses a mechanism called "delegation," which divides domain management responsibilities into smaller units, managing necessary name resolution information in a distributed manner. These units of management are called "zones." A DNS server that manages the information for a specific zone is referred to as that zone's "DNS content server" or "authoritative DNS server." On the other hand, servers that handle user queries, send their own queries to other DNS servers, and return the results to users are referred to as "DNS caching servers."
DNS servers are indispensable for the operation of the modern internet. However, DNS servers with vulnerabilities are prone to malicious attacks. Known attacks of this type include "delegation/transfer notification injection attacks" and "DNS flood attacks." To defend against these attacks, leveraging DNS proxies is highly effective. F5’s "F5 BIG-IP" comes equipped with DNS proxy functionality, offering robust solutions to mitigate such threats.