DNSoverHTTP 介绍
DNSoverHTTP 是基于 HTTP 协议的 DNS 实现。它是一个代理 DNS，是一个在 HTTP 基础上实现 DNS 的方法，提供了：
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一个 FastCGI 端点连接 Web 服务器和 DNS 服务器（Nginx、Apache 和 Bind）
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一个 DNS 代理服务器用于 /etc/resolv.conf 或者 DHCP 声明，使用 upstream HTTP 来解析 DNS
The great advantage to this approach is that HTTP usually makes it through
even the worst coffee shop or hotel room firewalls, since commerce may be at
stake. We also benefit from HTTP’s persistent TCP connection pool concept,
which DNS on TCP/53 does not have. Lastly, HTTPS will work, giving privacy.
This software is as yet unpackaged, but is portable to FreeBSD 10 and Debian 7
and very probably other BSD-similar and Linux-similar systems. This software
is written entirely in C and has been compiled with GCC and Clang with “full
warnings” enabled.