@Override
  public void receive(Address sender, byte[] data, int offset, int length) {
    if (data == null || length <= 0) { // GEODE-1596 - check for empty messages
      return;
    }

    // drop message from self; it has already been looped back up
    // (https://issues.jboss.org/browse/JGRP-1765)
    if (local_physical_addr != null && local_physical_addr.equals(sender)) {
      return;
    }

    if (length - offset == 4 && data[offset] == 'p' && data[offset + 1] == 'i'
        && data[offset + 2] == 'n' && data[offset + 3] == 'g') {
      // AvailablePort check
      data[offset + 1] = 'o';
      try {
        sendToSingleMember(sender, data, offset, length);
      } catch (Exception e) {
        log.fatal("Unable to respond to available-port check", e);
      }
      return;
    }

    super.receive(sender, data, offset, length);
  }
This is the initial part of the name of all JGroups threads that deliver messages
geode-membership/src/main/java/org/apache/geode/distributed/internal/membership/gms/messenger/Transport.java