Hello, I'm developing a simple STUN client with PJNATH. I must define 3 callback but my application is never on the defined callback. The application works well and it is able to send a Binding Request to a STUN server and it receive the response correctly. Here is my callback assignation. pj_memset(&m_pj_nath_stun_socket_callback, 0, sizeof(m_pj_nath_stun_socket_callback)); m_pj_nath_stun_socket_callback.on_rx_data = &(stunClientWindow::stun_sock_on_rx_data); m_pj_nath_stun_socket_callback.on_status = &(stunClientWindow::on_stun_status_callback); m_pj_nath_stun_socket_callback.on_data_sent = &(stunClientWindow::on_stun_request_callback); void * data; m_pj_status = pj_stun_sock_create(&m_pj_nath_stun_config, "STUN SOCKET", PJ_AF_INET, &m_pj_nath_stun_socket_callback, &m_pj_nath_stun_socket_config, &data, &m_pj_nath_stun_socket); Thanks for you help. cyrill gremaud