code: public static void unPublishPort(final OtpLocalNode node) {
          OtpTransport s = null;
  
          try {
              s = node.createTransport((String) null, EpmdPort.get());
              @SuppressWarnings("resource")
              final OtpOutputStream obuf = new OtpOutputStream();
              obuf.write2BE(node.alive().length() + 1);
              obuf.write1(stopReq);
              obuf.writeN(node.alive().getBytes());
              obuf.writeToAndFlush(s.getOutputStream());
              // don't even wait for a response (is there one?)
              if (traceLevel >= traceThreshold) {
                  System.out.println("-> UNPUBLISH " + node + " port="
                          + node.port());
                  System.out.println("<- OK (assumed)");
              }
          } catch (final Exception e) {/* ignore all failures */
          } finally {
              try {
                  if (s != null) {
                      s.close();
                  }
              } catch (final IOException e) { /* ignore close failure */
              }
              s = null;
          }
      }
docs: Unregister from Epmd. Other nodes wishing to connect will no longer be
  able to.
  
  <p>
  This method does not report any failures.