Ping
Ping monitoring
Is it there, and is the link to it losing packets.
What it is for
The simplest question you can ask a machine: does it answer at all. A router, a firewall, a server with no public service, a piece of hardware in a rack: things with an address and nothing else to talk to.
Ping is ICMP echo, and it reports packet loss as well as reachability, so a link that is up and dropping a fifth of its traffic is visible as something other than fine. If what you care about is a service on a port rather than the host, the TCP port check is the one that knows the difference.
Like every check here, it runs from Amsterdam, New York and Singapore, and a failure is confirmed from a second continent before anybody is woken. How that works.
What you can set
Everything below is on the form when you add one, on every plan.
- Host or IP address
- A hostname or an address. No port: ping is not a connection to anything on the host, it is the host answering.
Questions
What does the ping check actually measure?
Four ICMP echo requests, half a second apart, and it reports the packet loss as a percentage along with the latency: the minimum, average and maximum round trip time. Four rather than one, so a single dropped packet on a busy link is visible as loss rather than read as an outage.
Is partial packet loss up or down?
Neither, which is the honest answer and the one this product gives. A host answering one ping in four is not down and it is certainly not fine. Total loss is down, because nothing is answering. Loss over 20% on several checks in a row is degraded, which alerts without pretending the host has gone.
Do you report jitter?
Not as a number, and we would rather say so than compute something from four packets and put the word on it. What you get is the minimum, the average and the maximum round trip time for every check, and the spread between the first and the last is the thing you would have been reading anyway.
What about a host that does not answer ping?
Plenty of hosts and firewalls drop ICMP on purpose, and to a ping check that is indistinguishable from a host that is gone: every echo is lost, so it is down. If the host runs a service, watch its port with the TCP port check instead, which does not need ICMP at all.