Appendix C. Probes 235average against the Warning and Critical threshold levels. The required Packets to sendvalue allows you to control how many ICMP ECHO packets are sent to the system. Thisprobe collects the following metrics:• Round-Trip Average — The time it takes in milliseconds for the ICMP ECHO packet totravel to and from the monitored system.• Packet Loss — The percent of data lost in transit.Although optional, the IP Address field can be instrumental in collecting metrics for sys-tems that have multiple IP addresses. For instance, if the system is configured with multiplevirtual IP addresses or uses Network Address Translation (NAT) to support internal and ex-ternal IP addresses, this option may be used to check a secondary IP address rather thanthe primary address associated with the hostname.Note that this probe conducts the ping from an RHN Server and not the monitored system.Populating the IP Address field does not test connectivity between the system and thespecified IP address but between the RHN Server and the IP address. Therefore, enteringthe same IP address for Ping probes on different systems accomplishes precisely the sametask. To conduct a ping from a monitored system to an individual IP address, use theRemote Ping probe instead. Refer to Section C.8.7 Network Services::Remote Ping.Field ValueIP Address (defaults to system IP)Packets to send* 20Timeout* 10Critical Maximum Round-Trip AverageWarning Maximum Round-Trip AverageCritical Maximum Packet LossWarning Maximum Packet LossTable C-41. Network Services::Ping settingsC.8.6. Network Services::POP MailThe Network Services::POP Mail probe determines if it can connect to the POP3 port onthe system. A port number must be specified; specifying another port number overrides thedefault port 110. This probe collects the following metric:
