Knot DNS is described as 'high-performance authoritative-only DNS server which supports all key features of the domain name system including zone transfers, dynamic updates and DNSSEC' and is an app in the Network & Admin category. There are six alternatives to Knot DNS for Linux, Mac, Windows, BSD and Self-Hosted solutions. The best alternative is BIND, which is both free and Open Source. Other great apps like Knot DNS are PowerDNS (Free, Open Source), djbdns (Free, Open Source), MaraDNS (Free, Open Source) and NSD (Free, Open Source).
PowerDNS is a DNS Server that runs on most Unix derivatives. PowerDNS features a large number of different backends ranging from simple BIND style zonefiles to relational databases and load balancing/failover algorithms. A DNS recursor is also included as a separate program.
The djbdns software package is a collection of Domain Name System tools created by Daniel J. Bernstein. It includes software for all the fundamental DNS operations and several DNS debugging tools which administrators use to diagnose misconfigured remote servers.
MaraDNS implements the Domain Name System (DNS), an essential internet service. MaraDNS is open source software: This means that anyone is free to download, use, and modify the program free of charge, as per its license.