companion object {
    /**
     * A network that resolves only one IP address per host. Use this when testing route selection
     * fallbacks to prevent the host machine's various IP addresses from interfering.
     */
    private val SINGLE_INET_ADDRESS_DNS =
      Dns { hostname ->
        val addresses = Dns.SYSTEM.lookup(hostname)
        listOf(addresses[0])
      }

  //
  if (b != address.size) {
    if (compress == -1) return null // Address didn't have compression or enough groups.
    address.copyInto(address, address.size - (b - compress), compress, b)
    address.fill(0.toByte(), compress, compress + (address.size - b))
  }

  return address
}

/** Decodes an IPv4 address suffix of an IPv6 address, like 1111::5555:6666:192.168.0.1. */

In the DNS server(s) you would configure a record (an "`A record`") to point **your domain** to the public **IP address of your server**.

You would probably do this just once, the first time, when setting everything up.

/// tip

This Domain Name part is way before HTTPS, but as everything depends on the domain and the IP address, it's worth mentioning it here.

///

## `fastapi run` { #fastapi-run }

Executing `fastapi run` starts FastAPI in production mode.

    /**
     * Retrieve all addresses of a host by it's address. NetBIOS hosts can
     * have many names for a given IP address. The name and IP address make the
     * NetBIOS address. This provides a way to retrieve the other names for a
     * host with the same IP address.
     *
     * @param addr the address to query
     * @return array of NetBIOS addresses
     * @throws UnknownHostException if address cannot be resolved
     */

@defaultMessage Resolve hosts explicitly to the address(es) you want with InetAddress.
java.net.InetSocketAddress#<init>(java.lang.String,int)
java.net.Socket#<init>(java.lang.String,int)
java.net.Socket#<init>(java.lang.String,int,java.net.InetAddress,int)

@defaultMessage Don't bind to wildcard addresses. Be specific.
java.net.DatagramSocket#<init>()
java.net.DatagramSocket#<init>(int)

    proxySelector.assertRequests(address.url.toUri())
  }

  @Test fun proxySelectorReturnsMultipleProxies() {
    val address = factory.newAddress()
    proxySelector.proxies.add(proxyA)
    proxySelector.proxies.add(proxyB)
    val routeSelector = newRouteSelector(address)
    proxySelector.assertRequests(address.url.toUri())

    // First try the IP addresses of the first proxy, in sequence.

			TCPOptions{},
		)
		for _, err := range errs {
			if err != nil {
				if strings.Contains(err.Error(), "The requested address is not valid in its context") {
					// Ignore if IP is unbindable.
					continue nextTest
				}
				if strings.Contains(err.Error(), "bind: address already in use") {
					continue nextTest
				}
				t.Fatalf("Test %d: error: expected = <nil>, got = %v", i+1, err)
			}
		}

			Optional:    true,
			Type:        "number",
		},
	}

	HelpNATS = config.HelpKVS{
		config.HelpKV{
			Key:         target.NATSAddress,
			Description: "NATS server address e.g. '0.0.0.0:4222'",
			Type:        "address",
			Sensitive:   true,
		},
		config.HelpKV{
			Key:         target.NATSSubject,
			Description: "NATS subscription subject",
			Type:        "string",
		},
		config.HelpKV{

### TLS mit SNI-Erweiterung { #tls-with-sni-extension }

**Nur ein Prozess** im Server kann an einem bestimmten **Port** einer bestimmten **IP-Adresse** lauschen. Möglicherweise gibt es andere Prozesse, die an anderen Ports dieselbe IP-Adresse abhören, jedoch nur einen für jede Kombination aus IP-Adresse und Port.

TLS (HTTPS) verwendet standardmäßig den spezifischen Port `443`. Das ist also der Port, den wir brauchen.