AiThority.com Primer: What is Anycast DNS?
If you have been following the belligerent growth of cyber threats in recent times, you would have come across hundreds of surface attacks arising due to poor deployment of security measures in the Cloud Computing, VPN and Telecom capabilities. As we head into the most prolific phase of the IP-based communications era, powered by 5G and AI MLops, we ought to know how DNS security works, and what are the various technical terms associated with it.
In this AiThority.com Primer article, we are deep-diving into the world of anycast DNS, it’s definitions and its effectiveness in defending against DDoS or bot attacks.
What is Anycast DNS?
Anycast DNS is an incident management system that provides resilience to the IT network in case of a connection failure. Multiple DNS could be available for preventing data loss, but anycast and Dynamic DNS updates are the most widely used IP address management techniques that help to administer existing servers, moving ISPs or mobile hotspots.
Anycast Addressing is the process of assigning one IP address to multiple servers. This means multiple DNS servers are available to answer DNS queries — and the fastest would be the first to respond. The geographically-closest DNS server is often the fastest to do it in many cases.
Anycast DNS is a standard network addressing and routing system used with the CDN to deliver content to multiple routing paths (two or more end-point devices) using a single destination address.
Anycast is among the five network addressing systems assigned by the IP. The other four systems are:
- Unicast: One-to-one communication topology
- Broadcast: One-to-all association with one sender and multiple endpoints with replicating datagrams
- Multicast: One-to-sub-to-many or many-to-sub-to-many associations, where simultaneous datagrams are transmitted from multiple users to many endpoint devices
- Geocast: Specialized multicast, with limited CDN operation based on geographical locations
Anycast: specialized speed-optimized addressing based on one-to-one-of-many.
When combined with multiple geocast addressing servers, Anycast can be implemented across multiple locations (geographically isolated or connected) using the Border Gateway Protocol (BGP). There are multiple hosts with the same unicast IP address but different routes merged to the address. These are all connected through the BGP to ensure content reaches endpoint destinations via the least congested route at the fastest speed and optimized cost.
A Quick Overview on DNS
The Domain Name System (DNS) is a complex hierarchical and decentralized naming directory or a protocol used to assign names to connected devices- computers, mobile devices, or private networks. It is maintained by a Distributed Database system that can at least have one DNS server that publishes the information in a directory-based format– called name servers.DNS operations are very complex and they mostly control the information associated with the domain names, following underlying IP protocol/ TTLs and improver DNS caching process for better data communication exchanges.
There are 4 types of DNS servers involved in the CDN operations. These are:
- DNS recursor
- Root Name Server
- TLD Name Server
- Authoritative Name Server
What Anycast DNS does?
Apart from securing the server connection from interruptions during critical operations, anycast DNS actually optimizes the latency measurements and costs involved in driving traffic through contested paths. Anycast DNS chooses the least congested route to bring content to the end-user at the fastest speed.
Anycast keeps the DNS active, even when the resolver goes offline, the DNS shall answer the queries through various local nodes.
This is the exact reason why an Indian telecom company BSNL Limited decided to implement anycast DNS 220.127.116.11 to boost internet speed and connectivity.
Consumer demand for faster internet speeds and better geo-independent connectivity, we would see service providers increasingly undertaking anycast DNS integration. Anycast services (RFC 4786) is currently the most popular infrastructure for telecom operators.
Apart from reducing traffic congestion, Anycast DNS could be put in sync with Multicast Source Discovery Protocol (MSDP) to further improve load-sharing capabilities. We call that Anycast rendezvous point in synchronized load sharing methodology with other DNS applications.
Current Security Challenges
We are yet to analyze fully the security infringements arising from the anycast topology. Theoretically, like any other internet DNS system, anycast too, faces latent risks, including IP hijacking at the rendezvous point. Intermediate router, which is the hijacking unit, could accept packet from the sender, and block the route to anycast destinations. It is similar to IP hijacking in conventional DDoS attacks.
Yet, anycast DNS is significantly more reliable and secured due to its automated routing capabilities. Especially, when we are aiming to grow our footprints in 5G networking and connect as many IoT devices and sensors, anycast DNS addressing holds the key to our successful evolution in the 5G era. We are still identifying the various MOs used by attackers to hit anycast deployments using local and global nodes, similar to those used in unicast.
(To share your insights on DNS and DDoS safety measures, please write to us at firstname.lastname@example.org)