As a rule, every device or server that’s directly connected to the Internet has a unique IP address which is then used for 1:1 communication. This is known as unicast technology.
Here, a sender addresses a dedicated receiver directly, meaning that the request for a website, for example, is sent to exactly one server and is only answered by this server. This server is clearly identified by its IP address.
Anycast, on the other hand, is a routing and addressing method in which an entire group of servers is addressed with a single IP address. The servers in such an Anycast cloud are distributed across locations in different parts of the world. This is also called an Anycast cluster or Anycast cloud.
The advantages of Anycast:
Anycast offers greater reliability of DNS via the placement of multiple geographically spread out servers at the same IP address. If a DNS Anycast server becomes unavailable due to failure or because of routine maintenance, there will be very little impact on name resolution service as the service routes are withdrawn from the routing tables. Routing will redivert this traffic to new replacement best path servers in the Anycast group. Because of the redundancy of these DNS servers, the service is more available, and therefore, reliable.
An Anycast DNS structure offers greater security against DNS attacks that attempt to overwhelm servers and paralyze them by compelling them to crash or deny further requests. This is because the Anycast network is designed to maximise the use of resources, such as bandwidth, to handle a very high volume of requests. This allows the necessary time for security experts to notice the attacks and carry out appropriate countermeasures.
Simplified DNS configuration
Anycast DNS makes it possible to use the same name server IP addresses for all DNS client resolvers, without requiring imaging, DHCP templates or static multi-IP configurations. It does this by making the configuration of client DNS resolvers simpler.
Because Anycast is more direct in reaching an intermediary node, fewer internet hops are required. As there is a quicker request round trip (RTT) time, reduced latency boosts user experience.
Automatic load balancing
Anycast improves site speed by routing multiple servers to effectively balance load among DNS servers, especially if all routes have equal cost.
With all the advantages that Anycast offers, Fasthosts have now introduced it to all of its domains.