7.5 ICMP Pings

If a client has pending requests on a connection to an Active Directory server but has not received any responses to any of those requests for a period of time specified by ADConnection.LDAP_OPT_PING_KEEP_ALIVE, as tracked by the pingKeepAliveTimer on the ConnectionInfo structure that holds the TCP connection to that server, the client pings the directory server by sending an ICMP echo message as described in [RFC792] and waiting up to ADConnection.LDAP_OPT_PING_WAIT_TIME milliseconds for any echo reply from the corresponding server. If no such reply is received, the client repeats the process of pinging the server up to ADConnection.LDAP_OPT_PING_LIMIT times. If the client receives no response after sending the maximum number of pings, or receives an error from the underlying network implementation during this process, it triggers the Processing Network Errors (section 7.6.3.1) event.