code: public static void configurePorts(ServerBuilder server, List<Port> ports) {
          requireNonNull(server, "server");
          requireNonNull(ports, "ports");
          ports.forEach(p -> {
              final String ip = p.getIp();
              final String iface = p.getIface();
              final int port = p.getPort();
              final List<SessionProtocol> protocols = p.getProtocols();
  
              if (ip == null) {
                  if (iface == null) {
                      server.port(new ServerPort(port, protocols));
                  } else {
                      try {
                          final Enumeration<InetAddress> e = NetworkInterface.getByName(iface).getInetAddresses();
                          while (e.hasMoreElements()) {
                              server.port(new ServerPort(new InetSocketAddress(e.nextElement(), port),
                                                         protocols));
                          }
                      } catch (SocketException e) {
                          throw new IllegalStateException("Failed to find an iface: " + iface, e);
                      }
                  }
              } else if (iface == null) {
                  if (NetUtil.isValidIpV4Address(ip) || NetUtil.isValidIpV6Address(ip)) {
                      final byte[] bytes = NetUtil.createByteArrayFromIpAddressString(ip);
                      try {
                          server.port(new ServerPort(new InetSocketAddress(
                                  InetAddress.getByAddress(bytes), port), protocols));
                      } catch (UnknownHostException e) {
                          // Should never happen.
                          throw new Error(e);
                      }
                  } else {
                      throw new IllegalStateException("invalid IP address: " + ip);
                  }
              } else {
                  throw new IllegalStateException("A port cannot have both IP and iface: " + p);
              }
          });
      }
docs: Adds {@link Port}s to the specified {@link ServerBuilder}.