* @param port a port number from [0..65535]
   * @return if parsing was successful, a populated HostAndPort object.
   * @throws IllegalArgumentException if {@code host} contains a port number, or {@code port} is out
   *     of range.
   */
  public static HostAndPort fromParts(String host, int port) {
    checkArgument(isValidPort(port), "Port out of range: %s", port);

public class SampleServer extends Dispatcher {
  private final SSLContext sslContext;
  private final String root;
  private final int port;

  public SampleServer(SSLContext sslContext, String root, int port) {
    this.sslContext = sslContext;
    this.root = root;
    this.port = port;
  }

  public void run() throws IOException {
    MockWebServer server = new MockWebServer();

    // No port, bad default.
    checkFromStringCase("google.com", -1, "google.com", -1, false);
    checkFromStringCase("192.0.2.1", 65536, "192.0.2.1", -1, false);
    checkFromStringCase("[2001::1]", -1, "2001::1", -1, false);
    checkFromStringCase("2001::3", 65536, "2001::3", -1, false);
  }

  public void testFromStringUnusedDefaultPort() {
    // Default port, but unused.

    // No port, bad default.
    checkFromStringCase("google.com", -1, "google.com", -1, false);
    checkFromStringCase("192.0.2.1", 65536, "192.0.2.1", -1, false);
    checkFromStringCase("[2001::1]", -1, "2001::1", -1, false);
    checkFromStringCase("2001::3", 65536, "2001::3", -1, false);
  }

  public void testFromStringUnusedDefaultPort() {
    // Default port, but unused.

**Only one process** in the server can be listening on a specific **port** in a specific **IP address**. There could be other processes listening on other ports in the same IP address, but only one for each combination of IP address and port.

TLS (HTTPS) uses the specific port `443` by default. So that's the port we would need.

As only one process can be listening on this port, the process that would do it would be the **TLS Termination Proxy**.

                                    <label for="port" class="col-sm-3 text-sm-right col-form-label"><la:message
                                            key="labels.file_auth_port"/></label>
                                    <div class="col-sm-9">
                                        <la:errors property="port"/>
                                        <la:text styleId="port" property="port" styleClass="form-control"/>

**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.

                                    <label for="port" class="col-sm-3 text-sm-right col-form-label"><la:message
                                            key="labels.webauth_port"/></label>
                                    <div class="col-sm-9">
                                        <la:errors property="port"/>
                                        <la:text styleId="port" property="port" styleClass="form-control"/>

                                                                test="${data.port==null||data.port==''}">
                                                            <la:message key="labels.file_auth_any"/>
                                                        </c:if> ${f:h(data.port)}</td>
                                                        <td>${f:h(data.fileConfig.name)}</td>

                                                                test="${data.port==null||data.port==''}">
                                                            <la:message key="labels.webauth_any"/>
                                                        </c:if> ${f:h(data.port)}</td>
                                                        <td>${f:h(data.webConfig.name)}</td>