Ping (ICMP) Monitoring

Check that a server or device is reachable on the network with ICMP ping

A ping monitor sends ICMP echo requests to a host and succeeds when the host replies. It tells you whether a machine is reachable, not whether a particular service on it is working.

When to use it

• Confirm a server or network device is online
• Watch a VPN endpoint or router that has no open TCP port
• Pair with Port and HTTP monitors to see at which layer a problem is

Ping checks run from UptimeIO’s probe locations over the public internet. The target must be publicly reachable: private and internal targets (private IP ranges such as 10.x, 172.16-31.x and 192.168.x, localhost, and names ending in .local, .internal or .lan) are not accepted.

Create a ping monitor

1. Enter the target

   Enter the Host or IP Address, a public hostname or IP address such as vpn.yourcompany.com or 203.0.113.10.

2. Set the interval

   In How often we check, choose the Check Interval. The shortest interval depends on your plan: 5 minutes on Free, 1 minute on Pro and Scale.

3. Choose probe locations

   UptimeIO probes from multiple locations. Pro and Scale can choose which locations run regular checks (at least one); Free uses automatic selection.

4. Review the ping settings

   ICMP Configuration shows the packet and timeout settings below. The defaults suit most hosts.

Settings

Setting	What it does	Default / options
Monitor Name	Name shown in your dashboard	Generated from the host, up to 80 characters
Host or IP Address	The machine to ping	Required
Check Interval	Time between checks	1 minute to 24 hours. Plan minimum applies
Packet Count	Number of echo requests sent per check, about one second apart	4 (1 to 10)
Packet Size	Size of each packet in bytes. The maximum, 1,472, is the largest that fits a standard network packet without being split	64 (1 to 1,472)
Timeout	Longest a check may take, in milliseconds. Must be shorter than the check interval. Packets not sent by then are not counted	10,000 ms (up to 60,000)
TTL (Time To Live)	Maximum network hops a packet may travel. Optional	System default (1 to 255)

Each check sends the number of echo requests set in Packet Count, each Packet Size bytes, and succeeds if at least one reply is received. It fails when every packet is lost, the host cannot be resolved, or the timeout passes. Because requests go out about one second apart, set the Timeout to at least the Packet Count in seconds, or the check ends before all packets are sent.

Example

• Host or IP Address: vpn.yourcompany.com
• Check Interval: 5 minutes
• Packet Count: 4
• Packet Size: 64
• Timeout: 10,000 ms

Results

Each check records whether it succeeded, the round-trip time, and packet statistics (packets sent and received, packet loss). Packet loss is calculated from the packets actually sent in that check.

An incident opens when the host stays unreachable. Because incidents need confirmation from several probe locations, a failure seen from only one location does not open one (see Understanding incidents).

Firewalls

Allow inbound ICMP echo requests (type 8) and echo replies (type 0) to the host. Many cloud providers block ICMP by default, so add an explicit rule in your security group, network security group or firewall.

Ping or port?

Compare	Ping (ICMP)	Port (TCP)
Checks	The host answers	A service accepts connections
Often blocked by firewalls	Yes	Rarely
Use for	”Is the server up?"	"Is the service up?”

Troubleshooting

100% packet loss

The host is down, ICMP is blocked, or the target is wrong. Check that the host is online, that the firewall allows ICMP, and try ping hostname from your own machine.

Unknown host

The name does not resolve. Check the spelling and the DNS records (nslookup hostname).

Timeouts

Raise the Timeout, check for a firewall that silently drops ICMP, and try with a probe location closer to the host.

Target not accepted

The target is private, internal, a test domain or one of UptimeIO’s own domains. Use a public hostname or IP.

Next steps

Port Monitoring

Monitor specific service ports

Notifications

Configure alerts for ping monitors