​Unicast DNS explained

To understand what Unicast is about, let’s briefly review the concept of routing. It’s a process of picking the most convenient path for the traffic in a network or across many networks.

If you think about networks, the Internet, for instance, there is constant communication. A continuous exchange of data that travels around, divided into packets. To deliver such an amount of data packets, from their source to their destination, definitely require a smart routing. 

Routing works based on routing information base (RIB) or routing tables. They are records of data that include the routes to different network destinations. Sometimes, they also have specific distances related to those routes. Administrators create these tables because they permanently monitor network traffic. Or they can be built through the routing protocols. That’s what they are made for.

There are different routing methods. Unicast is one of them.

What is Unicast?

Unicast is a routing method that works in a one-to-one way. Data is transferred from a source (sender) to only one destination node (receiver). If a sender wants to send the same message to different receivers through the Unicast method, it has to send a copy of that message to every receiver (one-to-one).

Since Unicast means a request sent from one sender to just one receiver, only both of them can interact in the defined route. Unicast is very used for data transmission by the Internet. Think, for instance, every time you click a link. You request HTTP data from a host (the one written in the link), then this host sends the data only to you. Network communications based on the Internet protocol (IP) can use Unicast as a routing method. 

Unicast DNS – deffinition

Unicast DNS is a routing method between DNS servers and DNS clients. In this case, a server (just one) holds the IP of a website. Due to this, users around the world can request the website, but all responses will come from this exact DNS server.

The natural consequence of this will be that users luckily located close to the DNS server location will get a fast answer. But users requesting from a faraway location from the DNS server’s one will have to wait longer. 

Pros of Unicast DNS

  • Cost-effective. It’s cheaper than other types of routing methods because it involves a single server. This is another reason for its popularity.
  • Ease of use. Unicast DNS means simplicity, one server, one IP. You or your administrator will be responsible for the performance and maintenance of a single server.
  • A great choice for local businesses. If your business is not international and has a clear target market, this is a very suitable alternative for you. You can be sure that every single user’s request will be punctually responded to. Latency won’t be a problem since the DNS server and your audience both share the same physical location.

Cons of Unicast DNS. 

  • Latency is a serious fact to consider. If you have expansion plans or you already run an international business, Unicast can’t fully satisfy users’ expectations located far from the DNS server.
  • No redundancy. When the availability of your website depends totally on a single DNS server, that can be risky. If it fails, if you have to shut it down for maintenance, for fixing an issue, or if it suffers an attack, your website’s availability can be compromised.


Unicast DNS is a basic but efficient solution widely used for routing communications. Analyze your business needs. Maybe it’s exactly what you need!

Anycast DNS vs. Unicast DNS

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