NAME

SYNOPSIS

 *** Probes ***

 +TCPPing

 binary = /usr/bin/tcpping # mandatory
 forks = 5
 offset = 50%
 step = 300
 timeout = 15

 # The following variables can be overridden in each target section
 /^influx_.+/ = influx_location = In the basement
 pings = 5
 port = 80

 # [...]

 *** Targets ***

 probe = TCPPing # if this should be the default probe

 # [...]

 + mytarget
 # probe = TCPPing # if the default probe is something else
 host = my.host
 /^influx_.+/ = influx_location = In the basement
 pings = 5
 port = 80

DESCRIPTION

The (optional) port option lets you configure the port for the pings sent. The TCPPing manpage has the following to say on this topic:

The problem is that with the widespread use of firewalls on the modern Internet, many of the packets that traceroute(8) sends out end up being filtered, making it impossible to completely trace the path to the destination. However, in many cases, these firewalls will permit inbound TCP packets to specific ports that hosts sitting behind the firewall are listening for connections on. By sending out TCP SYN packets instead of UDP or ICMP ECHO packets, tcptraceroute is able to bypass the most common firewall filters.

It is worth noting that tcptraceroute never completely establishes a TCP connection with the destination host. If the host is not listening for incoming connections, it will respond with an RST indicating that the port is closed. If the host instead responds with a SYN|ACK, the port is known to be open, and an RST is sent by the kernel tcptraceroute is running on to tear down the connection without completing three-way handshake. This is the same half-open scanning technique that nmap(1) uses when passed the -sS flag.

VARIABLES

binary

The location of your tcpping script.

Example value: /usr/bin/tcpping

This setting is mandatory.

forks

Run this many concurrent processes at maximum

Example value: 5

Default value: 5

offset

If you run many probes concurrently you may want to prevent them from hitting your network all at the same time. Using the probe-specific offset parameter you can change the point in time when each probe will be run. Offset is specified in % of total interval, or alternatively as 'random', and the offset from the 'General' section is used if nothing is specified here. Note that this does NOT influence the rrds itself, it is just a matter of when data acquisition is initiated. (This variable is only applicable if the variable 'concurrentprobes' is set in the 'General' section.)

Example value: 50%

step

Duration of the base interval that this probe should use, if different from the one specified in the 'Database' section. Note that the step in the RRD files is fixed when they are originally generated, and if you change the step parameter afterwards, you'll have to delete the old RRD files or somehow convert them. (This variable is only applicable if the variable 'concurrentprobes' is set in the 'General' section.)

Example value: 300

timeout

How long a single 'ping' takes at maximum

Example value: 15

Default value: 5

Supported target-specific variables:

/^influx_.+/

This is a tag that will be sent to influxdb and has no impact on the probe measurement. The tag name will be sent without the "influx_" prefix, which will be replaced with "tag_" instead. Tags can be used for filtering.

Example value: influx_location = In the basement

pings

How many pings should be sent to each target, if different from the global value specified in the Database section. Note that the number of pings in the RRD files is fixed when they are originally generated, and if you change this parameter afterwards, you'll have to delete the old RRD files or somehow convert them.

Example value: 5

port

The TCP port the probe should measure.

Example value: 80

AUTHORS