Transport Configuration

The library supports multiple transport protocols with advanced configuration options for different DNS query scenarios.

TCP Transport

TCP transport with custom timeouts and keep-alive settings:

const client = new DnsClient({
  transport: {
    type: 'tcp',
    timeout: 5000,
    keepAlive: true,
    retries: 3
  }
})

TCP Options

Option	Type	Default	Description
timeout	number	5000	Connection timeout in milliseconds
keepAlive	boolean	false	Enable TCP keep-alive
retries	number	3	Number of retry attempts
port	number	53	TCP port number

DNS-over-TLS (DoT)

Secure DNS queries over TLS with certificate validation:

const tlsClient = new DnsClient({
  transport: {
    type: 'tls',
    serverName: 'dns.example.com',
    verify: true,
    port: 853
  }
})

TLS Options

Option	Type	Default	Description
serverName	string	Required	Server hostname for certificate validation
verify	boolean	true	Enable certificate verification
port	number	853	TLS port number
timeout	number	5000	Connection timeout in milliseconds

DNS-over-HTTPS (DoH)

Modern HTTPS-based DNS transport with custom headers:

const dohClient = new DnsClient({
  transport: {
    type: 'https',
    url: 'https://dns.example.com/dns-query',
    headers: {
      Accept: 'application/dns-json'
    }
  }
})

HTTPS Options

Option	Type	Default	Description
url	string	Required	DoH endpoint URL
headers	Record<string, string>	{}	Custom HTTP headers
timeout	number	5000	Request timeout in milliseconds

Advanced Transport Features

Connection Pooling

For high-performance scenarios:

const client = new DnsClient({
  transport: {
    type: 'tcp',
    poolSize: 5,
    poolTimeout: 30000,
    keepAlive: true
  }
})

Load Balancing

Using multiple DNS servers:

const client = new DnsClient({
  transport: {
    type: 'tcp',
    servers: [
      { host: 'dns1.example.com', port: 53 },
      { host: 'dns2.example.com', port: 53 }
    ],
    strategy: 'round-robin' // or 'random', 'failover'
  }
})

Retry Strategy

Custom retry logic:

const client = new DnsClient({
  transport: {
    type: 'tcp',
    retries: 3,
    retryStrategy: (attempt, error) => {
      // Exponential backoff with jitter
      const delay = Math.min(100 * 2 ** attempt, 2000)
      return delay + Math.random() * 100
    }
  }
})