Why Should an ISP Have Its Own Recursive DNS?


Why Should an ISP Have Its Own Recursive DNS?

By Uesley Correa – Telecommunications Speaker | IPv6 Evangelist | ISP Solutions | ISP Trainer | Skills Developer

In the world of IT and telecommunications, the importance of an ISP having its own recursive DNS is often overlooked. As I travel to courses and events in various countries, I often ask about this and many ISPs don’t even understand the need to have a DNS; in fact, some don’t even know how the Internet works. However, this technical decision can have a significant impact on performance, security, and customer satisfaction.

1. Performance and speed

When an ISP chooses to use its own recursive DNS, it has full control over the performance and speed of this critical service. Having your own recursive DNS allows faster access to websites by avoiding the delay associated with querying external DNS servers. Likewise, having your own recursive DNS increases network efficiency by minimizing traffic to and from external DNS servers, as once the initial query to a domain is loaded into the local DNS cache, it will stay there until the end of the TTL. And while it remains in the local DNS cache, there is no need to query the same domain on external root servers once again.

2. Security

Security is another area that requires attention and care. An ISP that has its own recursive DNS has greater control over the security policies that are applied to DNS requests. This can help protect customers against online threats such as phishing or malware attacks by blocking access to dangerous or fraudulent websites. And the ISP is a major player in improving browsing security.

3. Customization and control

Having your own recursive DNS server allows for a greater degree of customization and control. An ISP can configure and optimize its DNS to better meet the needs of its customers and adapt to changing network conditions. Techniques such as HyperLocal and Anycast can be implemented to increase the availability of the service. The benefits of the DNS can also be leveraged to comply with regulatory obligations such as website blocking and others.


An ISP that implements its own recursive DNS can significantly improve the performance and security of its network, while offering its customers a more efficient and personalized service. It is an investment worth making, as it benefits not only the ISP but also its customers. Try it and see for yourself!

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