Overview

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DnsClient sends DNS queries to one server, over the transport you choose, and returns the parsed response. It is a client for a resolver or an authoritative server you name: it does not read the DNS configuration of the machine and does not resolve names recursively by itself.

using var client = new DnsClient(serverAddress, DnsClientProtocol.Udp);
var response = await client.QueryAsync("www.example.com", DnsQueryType.A);

Assert.Equal(DnsResponseCode.NoError, response.Header.ResponseCode);
var addresses = response.Answers.OfType<DnsARecord>().Select(record => record.Address).ToList();
Assert.Equal([IPAddress.Parse("192.0.2.10")], addresses);

Options

DnsClientOptions is the third argument of the constructor:

Option	Default	Use
Timeout	5 seconds	How long to wait for a response. `Timeout.InfiniteTimeSpan` disables it. See Errors and timeouts.
EnableEdns	`true`	Adds an EDNS(0) OPT record to the queries.
EdnsUdpPayloadSize	1232	The largest UDP response the client accepts, advertised in the OPT record.
RetryTruncatedOverTcp	`true`	Sends the query again over TCP when a UDP response is truncated. See Truncated responses.
DnssecOk	`false`	Asks for the DNSSEC records. See DNSSEC.
DnssecValidationMode	None	Local validates the DNSSEC chain of trust. See DNSSEC.
DnssecTrustAnchors	DnssecTrustAnchors.Root	The trust anchors of local validation.
TimeProvider	`TimeProvider.System`	The clock used to check the validity period of DNSSEC signatures.
HttpHandler, HttpVersion, HttpVersionPolicy	a pooled handler, HTTP/2, `RequestVersionOrLower`	DNS over HTTPS only. See DNS over HTTPS.
ServerAddressResolver	the system resolver	Resolves the host name of the server. See Server address.