Add Knot and Yadifa in DNS category

README.md

@@ -112,9 +112,11 @@ A curated list of amazingly awesome open source sysadmin resources inspired by [
 
 * [Bind](https://www.isc.org/downloads/bind/) - The most widely used name server software.
 * [djbdns](http://cr.yp.to/djbdns.html) - A collection of DNS applications, including tinydns.
+* [Knot](https://www.knot-dns.cz/) - High performance authoritative-only DNS server.
 * [NSD](http://www.nlnetlabs.nl/projects/nsd/) - Authoritative only, high performance, simple name server.
 * [PowerDNS](https://www.powerdns.com/) - DNS server with a variety of data storage back-ends and load balancing features.
 * [Unbound](http://unbound.net/) - Validating, recursive, and caching DNS resolver.
+* [Yadifa](http://yadifa.eu/) - Lightweight authoritative Name Server with DNSSEC capabilities powering the .eu top-level domain.
 
 ## Hosting Control Panels
 *Web hosting control panels*