private void startServer(int systemId, int locatorPort, int remoteSystemId, String remoteName,
      int receiverPort) throws IOException {
    cacheRule.createCache(createServerConfig(locatorPort));

    String uniqueName = "server-" + systemId;
    File[] dirs = new File[] {temporaryFolder.newFolder(uniqueName)};

    GatewaySenderFactory senderFactory = createGatewaySenderFactory(dirs, uniqueName);
    GatewaySender sender = senderFactory.create(remoteName, remoteSystemId);
    sender.start();

    GatewayReceiverFactory receiverFactory = createGatewayReceiverFactory(receiverPort);
    GatewayReceiver receiver = receiverFactory.create();
    receiver.start();

    RegionFactory<Integer, Integer> regionFactory =
        cacheRule.getCache().createRegionFactory(RegionShortcut.REPLICATE);
    regionFactory.addGatewaySenderId(remoteName);

    regionFactory.create(REGION_NAME);
  }
Use of SECURITY_CLIENT_AUTHENTICATOR should result in the servers performing authentication
during HandShake of Gateway Sender/Receiver connecting.
geode-wan/src/distributedTest/java/org/apache/geode/internal/cache/wan/GatewayLegacyAuthenticationRegressionTest.java