【介绍】
DNS（domain name system）存储和关联域名的多组信息，最重要的是将域名与IP关联、将域名与邮件服务器关联。
参考：https://amon.org/dns-faq
参考：https://amon.org/bind
参考：https://amon.org/powerdnsdns
参考：https://blog.csdn.net/qinscx/article/details/42387987
【源码】
Knot DNS：
Knot DNS由捷克共和国国家顶级域.CZ注册管理局CZNIC对外发布，是一款高性能DNS服务器软件，支持所有DNS系统的关键特性，包括区传输、动态更新以及 DNSSEC等。
官网：http://www.knot-dns.cz
下载：https://www.knot-dns.cz/pages/download
介绍：https://en.wikipedia.org/wiki/Knot_DNS
以下是多个开源的DNS服务器及前端项目：
DNS服务器开源项目
BIND (Berkeley Internet Name Domain) is an implementation of the Domain Name System (DNS) protocols and provides an openly redistributable reference implementation of the major components of the Domain Name System.
Unbound：一个运行在 Linux 平台上的有效的、递归的、可缓存的的DNS解决方案。（Last Update: 2013-03-21）
DNSPod-SR（DNSPod Security Recursive DNS Server） ：一个运行在 Linux 平台上的高性能的递归 DNS 服务器软件，具备高性能、高负载、易扩展的优势。
djbdns： a simple and secure DNS implementation created by Daniel J. Bernstein due to his frustrations with repeated BIND security holes.
dents：a server implementation of the Internet’s Domain Name System with a focus on security, maintability and extensibility via modules.
Xyria:DNSd：a high performance DNS server that supports only the most important features and resource records while being extremely fast and secure. It also supports round-robin load balancing.
PowerDNS：a versatile DNS server, written in C++ and licensed under the GPL. It runs on most Unix derivatives and on Microsoft Windows. 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. Anecdotal evidence suggests that around 10% of all world domains are powered by this nameserver, 49% of the German .DE zone and 7% of the .NET zone.
pdnsd：a proxy DNS server with permanent caching (the cache contents are written to hard disk on exit) that is designed to cope with unreachable or down DNS servers (for example in dial-in networking).
MaraDNS：a package that implements the Domain Name Service (DNS), an essential internet service.
Dual DHCP DNS Server：Combined DHCP/DNS Server for Small LAN. DHCP Server alots/renew host addresses and DNS Server first try resolving from DHCP alotted names then from Cache then only forwarding to External DNS Servers. BOOTP Suppot, Auto Config and auto Dynamic DNS update.
Oak DNS Server： an authoritative and recursive DNS Server. It supports most modern nameserver features and is intended as an alternative for BIND.
sheerdns：a master DNS server whose zone records are stored on a One-Record-Per-File bases. Because of this, it is the simplest of any DNS to configure, the easiest to update, and the most efficient for networks that experience a lot of updates (for example master servers for dynamic IP address ranges). You never have to restart it; any updates are available immediately without having to notify the sheerdns process.
Zero Calorie DNS Server：a domain name server for which the binary weighs in at 26K, that has no dependencies other than the minimal FreeBSD 6.0 installation. The server responds to “name server” (NS), “start of authority” (SOA), “address record” (A), “reverse address” (PTR), and “mail exchanger” (MX) requests. The server is fairly fast because the feature set has been trimmed down to the bare minimum. A few things are hard-coded so that a two minute setup is easy to accomplish. The hard-coding means that it may not be for everyone, however.
DNS前端/客户端开源项目
WeBBind：a Web interface for admin BIND DNS servers. It is written in PHP for everyday usage.
DNS Control：a Web-based DNS management tool for BIND 9. It supports maintaining A, MX, and CNAME records, with all information stored in a MySQL database using ADODB. The system is completly templatable as it uses the Smarty template engine
ProBIND：a Web application for administrating one or more BIND servers. It is intended for small to medium sized ISPs, but there is no reason why it couldn’t be used wherever many zones must be managed across a set of master and slave servers.
mysqlBind：myqslBind manages multiple DNS/BIND (8 and 9) name servers. It automates updates to multiple DNS servers, centralizes and stores all zone and resource records for sets of related name servers (ns0…nsN.yourisp.net), and even manages different name server sets from a single browser-based interface. Unlimited master and slave name servers update their zone information via a job queue system that uses MySQL socket connections. Advanced operations can use mySQL replication clusters for high availability and redundancy. Large ISPs and other organizations should note that they can easily add SQL functions to customize the program for their special needs. It supports authentication via SSL Unix password login, SSL personal certificate, or IP-based access with multiple permission levels and individual record ownership. It is also compatible with mysqlISP.
GBindAdmin：an easy to use GTK+ frontend for ISC BIND. It handles multiple domains and can switch from master to slave domain in three clicks. It can change the domain name for entire domains and subdomains, including domain resources such as MX, A, AAAA, CNAME, and NS. It can also generate and set up secret keys for rndc and construct a chroot environment.
Binder：a program that provides a Web-based control panel to Bind 9. It is for small ISPs, small hosting companies, and individuals that host domains and want to provide their customers with an easy to use, simple interface to their records, without having to give up control of their nameservers.
dnSQLpanel：an easy to use control panel for Bind, using the MySQL SDB module. It provides direct access to the tables that Bind reads from modifying data in real time.
myWebDNS：a MySQL/PHP-Web based package to manage a DNS server configured with Bind 9. It permit to operate as administrator to create and manage the DNS, and as a user to create and manage the domains. The package as written completly in PHP and use Javascript for various checks.
BIND Webmin Module：Create and edit domains, DNS records, BIND options and views.
【服务】
评测：https://guozeyu.com/2018/11/azure-dns-ns1-constellix-compare/