import okhttp3.Dns.Companion.SYSTEM

/**
 * A domain name service that resolves IP addresses for host names. Most applications will use the
 * [system DNS service][SYSTEM], which is the default. Some applications may provide their own
 * implementation to use a different DNS server, to prefer IPv6 addresses, to prefer IPv4 addresses,
 * or to force a specific known IP address.
 *

    /**
     * Resolves the given host name to an array of IP addresses.
     * The host name is first converted to ASCII using IDN before resolution.
     * IPv6 addresses in bracket notation (e.g., [::1] or [2001:db8::1]) are
     * handled specially by removing the brackets before resolution.
     *
     * @param host the host name to resolve
     * @return an array of IP addresses for the host

  private var nextAddress = 0xff000064L // 255.0.0.100 in IPv4; ::ff00:64 in IPv6.

  /** Sets the results for `hostname`.  */
  operator fun set(
    hostname: String,
    addresses: List<InetAddress>,
  ): FakeDns {
    hostAddresses[hostname] = addresses
    return this
  }

  /** Clears the results for `hostname`.  */
  fun clear(hostname: String): FakeDns {
    hostAddresses.remove(hostname)
    return this
  }

    /**
     * Resolves the given host name to an array of IP addresses.
     * The host name is first converted to ASCII using IDN before resolution.
     * IPv6 addresses in bracket notation (e.g., [::1] or [2001:db8::1]) are
     * handled specially by removing the brackets before resolution.
     *
     * @param host the host name to resolve
     * @return an array of IP addresses for the host

        NbtAddress[] addresses = (NbtAddress[]) addressArrayField.get(response);
        assertEquals(numNames, addresses.length);

        // Verify each address has correct data
        for (int i = 0; i < numNames; i++) {
            assertNotNull(addresses[i]);
            assertTrue(addresses[i].isActive);
            assertFalse(addresses[i].groupName);
        }
    }

    @Test

	"github.com/minio/minio/internal/logger"
	xnet "github.com/minio/pkg/v3/net"
)

var (
	// IPv4 addresses of localhost.
	localIP4 = mustGetLocalIP4()

	// IPv6 addresses of localhost.
	localIP6 = mustGetLocalIP6()

	// List of all local loopback addresses.
	localLoopbacks = mustGetLocalLoopbacks()
)

// mustSplitHostPort is a wrapper to net.SplitHostPort() where error is assumed to be a fatal.

   * an IPv4 address or not.
   *
   * <p>IPv6 addresses are <b>coerced</b> to IPv4 addresses before being converted to integers.
   *
   * <p>As long as there are applications that assume that all IP addresses are IPv4 addresses and
   * can therefore be converted safely to integers (for whatever purpose) this function can be used
   * to handle IPv6 addresses as well until the application is suitably fixed.
   *

They're also concrete: each URL identifies a specific path (like `/square/okhttp`) and query (like `?q=sharks&lang=en`). Each webserver hosts many URLs.

### [Addresses](https://square.github.io/okhttp/5.x/okhttp/okhttp3/-address/)

Addresses specify a webserver (like `github.com`) and all of the **static** configuration necessary to connect to that server: the port number, HTTPS settings, and preferred network protocols (like HTTP/2).

    val result = proxies[nextProxyIndex++]
    resetNextInetSocketAddress(result)
    return result
  }

  /** Prepares the socket addresses to attempt for the current proxy or host. */
  @Throws(IOException::class)
  private fun resetNextInetSocketAddress(proxy: Proxy) {
    // Clear the addresses. Necessary if getAllByName() below throws!
    val mutableInetSocketAddresses = mutableListOf<InetSocketAddress>()

    @Test
    public void testIsIPv6Address() {
        // IPv6 addresses
        assertTrue(IpAddressUtil.isIPv6Address("::1"));
        assertTrue(IpAddressUtil.isIPv6Address("2001:db8::1"));
        assertTrue(IpAddressUtil.isIPv6Address("fe80::1"));
        assertTrue(IpAddressUtil.isIPv6Address("2001:0db8:0000:0000:0000:ff00:0042:8329"));

        // IPv4 addresses
        assertFalse(IpAddressUtil.isIPv6Address("127.0.0.1"));