3 Item types - 5 Simple checks - 《Zabbix v5.2 Manual》

5 Simple checks

5 Simple checks

Overview

Simple checks are normally used for remote agent-less checks of services.

Note that Zabbix agent is not needed for simple checks. Zabbix server/proxy is responsible for the processing of simple checks (making external connections, etc).

Examples of using simple checks:

net.tcp.service[ftp,,155]
net.tcp.service[http]
net.tcp.service.perf[http,,8080]
net.udp.service.perf[ntp]

User name and Password fields in simple check item configuration are used for VMware monitoring items; ignored otherwise.

Supported simple checks

List of supported simple checks:

See also:

VMware monitoring item keys

Key
	Description	Return value	Parameters	Comments

icmpping[<target>,<packets>,<interval>,<size>,<timeout>]
	Host accessibility by ICMP ping.	0 - ICMP ping fails 1 - ICMP ping successful	target - host IP or DNS name packets - number of packets interval - time between successive packets in milliseconds size - packet size in bytes timeout - timeout in milliseconds	Example: ⇒ icmpping[,4] → if at least one packet of the four is returned, the item will return 1. See also: table of default values.

icmppingloss[<target>,<packets>,<interval>,<size>,<timeout>]
	Percentage of lost packets.	Float.	target - host IP or DNS name packets - number of packets interval - time between successive packets in milliseconds size - packet size in bytes timeout - timeout in milliseconds	See also: table of default values.

icmppingsec[<target>,<packets>,<interval>,<size>,<timeout>,<mode>]
	ICMP ping response time (in seconds).	Float.	target - host IP or DNS name packets - number of packets interval - time between successive packets in milliseconds size - packet size in bytes timeout - timeout in milliseconds mode - possible values: min, max, avg (default)	If host is not available (timeout reached), the item will return 0. If the return value is less than 0.0001 seconds, the value will be set to 0.0001 seconds. See also: table of default values.

net.tcp.service[service,<ip>,<port>]
	Checks if service is running and accepting TCP connections.	0 - service is down 1 - service is running	service - possible values: ssh, ldap, smtp, ftp, http, pop, nntp, imap, tcp, https, telnet (see details) ip - IP address or DNS name (by default host IP/DNS is used) port - port number (by default standard service port number is used).	Example: ⇒ net.tcp.service[ftp,,45] → can be used to test the availability of FTP server on TCP port 45. Note that with tcp service indicating the port is mandatory. These checks may result in additional messages in system daemon logfiles (SMTP and SSH sessions being logged usually). Checking of encrypted protocols (like IMAP on port 993 or POP on port 995) is currently not supported. As a workaround, please use net.tcp.service[tcp,<ip>,port] for checks like these. https and telnet services are supported since Zabbix 2.0.

net.tcp.service.perf[service,<ip>,<port>]
	Checks performance of TCP service.	Float. 0.000000 - service is down seconds - the number of seconds spent while connecting to the service	service - possible values: ssh, ldap, smtp, ftp, http, pop, nntp, imap, tcp, https, telnet (see details) ip - IP address or DNS name (by default, host IP/DNS is used) port - port number (by default standard service port number is used).	Example: ⇒ net.tcp.service.perf[ssh] → can be used to test the speed of initial response from SSH server. Note that with tcp service indicating the port is mandatory. Checking of encrypted protocols (like IMAP on port 993 or POP on port 995) is currently not supported. As a workaround, please use net.tcp.service.perf[tcp,<ip>,port] for checks like these. https and telnet services are supported since Zabbix 2.0. Called tcp_perf before Zabbix 2.0.

net.udp.service[service,<ip>,<port>]
	Checks if service is running and responding to UDP requests.	0 - service is down 1 - service is running	service - possible values: ntp (see details) ip - IP address or DNS name (by default host IP/DNS is used) port - port number (by default standard service port number is used).	Example: ⇒ net.udp.service[ntp,,45] → can be used to test the availability of NTP service on UDP port 45. This item is supported since Zabbix 3.0, but ntp service was available for net.tcp.service[] item in prior versions.

net.udp.service.perf[service,<ip>,<port>]
	Checks performance of UDP service.	Float. 0.000000 - service is down seconds - the number of seconds spent waiting for response from the service	service - possible values: ntp (see details) ip - IP address or DNS name (by default, host IP/DNS is used) port - port number (by default standard service port number is used).	Example: ⇒ net.udp.service.perf[ntp] → can be used to test response time from NTP service. This item is supported since Zabbix 3.0, but ntp service was available for net.tcp.service[] item in prior versions.

Timeout processing

Zabbix will not process a simple check longer than the Timeout seconds defined in the Zabbix server/proxy configuration file.

ICMP pings

Zabbix uses external utility fping for processing of ICMP pings.

The utility is not part of Zabbix distribution and has to be additionally installed. If the utility is missing, has wrong permissions or its location does not match the location set in the Zabbix server/proxy configuration file (‘FpingLocation’ parameter), ICMP pings (icmpping, icmppingloss, icmppingsec) will not be processed.

See also: known issues

fping must be executable by the user Zabbix daemons run as and setuid root. Run these commands as user root in order to set up correct permissions:

shell> chown root:zabbix /usr/sbin/fping
shell> chmod 4710 /usr/sbin/fping

After performing the two commands above check ownership of the fping executable. In some cases the ownership can be reset by executing the chmod command.

Also check, if user zabbix belongs to group zabbix by running:

shell> groups zabbix

and if it’s not add by issuing:

shell> usermod -a -G zabbix zabbix

Defaults, limits and description of values for ICMP check parameters:

Parameter	Unit	Description	Fping’s flag	Defaults set by		Allowed limits by Zabbix
Parameter	Unit	Description	Fping’s flag	fping	Zabbix	min	max
packets	number	number of request packets to a target	-C		3	1	10000
interval	milliseconds	time to wait between successive packets	-p	1000		20	unlimited
size	bytes	packet size in bytes 56 bytes on x86, 68 bytes on x86_64	-b	56 or 68		24	65507
timeout	milliseconds	fping v3.x - timeout to wait after last packet sent, affected by -C flag fping v4.x - individual timeout for each packet	-t	fping v3.x - 500 fping v4.x - inherited from -p flag, but not more than 2000		50	unlimited

In addition Zabbix uses fping options -i interval ms (do not mix up with the item parameter interval mentioned in the table above, which corresponds to fping option -p) and -S source IP address (or -I in older fping versions). Those options are auto-detected by running checks with different option combinations. Zabbix tries to detect the minimal value in milliseconds that fping allows to use with -i by trying 3 values: 0, 1 and 10. The value that first succeeds is then used for subsequent ICMP checks. This process is done by each ICMP pinger process individually.

Auto-detected fping options are invalidated every hour and detected again on the next attempt to perform ICMP check. Set DebugLevel>=4 in order to view details of this process in the server or proxy log file.

Warning: fping defaults can differ depending on platform and version - if in doubt, check fping documentation.

Zabbix writes IP addresses to be checked by any of three icmpping* keys to a temporary file, which is then passed to **fping. If items have different key parameters, only ones with identical key parameters are written to a single file.
All IP addresses written to the single file will be checked by fping in parallel, so Zabbix icmp pinger process will spend fixed amount of time disregarding the number of IP addresses in the file.