Ae.Dns 
API Documentation: https://alanedwardes.github.io/docs/Ae.Dns/
A pure C# implementation of a DNS client, server and configurable caching/filtering layer. This project offers the following packages:
- Ae.Dns.Client - HTTP and UDP DNS clients with caching capabilities
- Ae.Dns.Server - Standard UDP DNS server
- Ae.Dns.Server.Http - HTTP DNS server (if coupled with SSL, a DoH server)
- Ae.Dns.Protocol - Low level DNS wire protocol round-trip handling used on the client and server
Ae.Dns.Client
Offers both HTTP(S) and UDP DNS clients, with a simple random client implementation.
Basic HTTPS Client Usage
This example is a very simple setup of the DnsHttpClient using the CloudFlare DNS over HTTPS resolver.
See samples/BasicHttpClient/Program.cs
Advanced HTTPS Client Usage
This example uses Microsoft.Extensions.Http.Polly to allow retrying of failed requests.
See samples/AdvancedHttpClient/Program.cs
Basic UDP Client Usage
This example is a basic setup of the DnsUdpClient using the primary CloudFlare UDP resolver.
See samples/BasicUdpClient/Program.cs
Random Client Usage
This example uses multiple upstream IDnsClient implementations in a random fashion using DnsRandomClient. Note that multiple protocols can be mixed, both the DnsUdpClient and DnsHttpClient can be used here since they implement IDnsClient.
See samples/RandomClient/Program.cs
Racer Client Usage
This example uses multiple (two or more) upstream IDnsClient implementations and races them using DnsRacerClient. Two queries are sent in parallel, and the fastest result "wins" (is returned). If a query faults, the other query result is used. As with the random client, multiple protocols can be mixed, both the DnsUdpClient and DnsHttpClient can be used here since they implement IDnsClient.
See samples/RacerClient/Program.cs
Caching Client Usage
This example uses the DnsCachingClient to cache queries into a MemoryCache, so that the answer is not retrieved from the upstream if the answer is within its TTL. Note that this can be combined with the DnsRandomClient, so the cache can be backed by multiple upstream clients (it just accepts IDnsClient).
See samples/CachingClient/Program.cs
Ae.Dns.Server
Offers a standard DNS UDP server.
Basic UDP Server
A example UDP server which forwards all queries via UDP to the CloudFlare DNS resolver, and blocks www.google.com.
See samples/BasicUdpServer/Program.cs
Advanced UDP Server
A more advanced UDP server which uses the DnsCachingClient and DnsRandomClient to cache DNS answers from multiple upstream clients, and the RemoteSetFilter to block domains from a remote hosts file.
See samples/AdvancedUdpServer/Program.cs
Ae.Dns.Server.Http
Offers an HTTPS (DoH) server for use with clients supporting the DNS over HTTPS protocol.
See samples/BasicHttpServer/Program.cs
Ae.Dns.Protocol
Provides the low-level protocol handling for the over-the-wire DNS protocol format as per RFC 1035.
HttpClient DNS Resolution Middleware
This package includes a DelegatingHandler for HttpClient which intercepts HTTP requests before they're sent across the wire, resolves the host with the specified IDnsClient, replaces the host with one of the resolved IP addresses, then sends the request to the IP address with the host as the Host header.
Basic DnsDelegatingHandler Example
See samples/BasicHttpClientMiddleware/Program.cs