Smokeping_probes_CiscoRTTMonDNS(3)

📦
version 2.9.0 · 12 versions
, in alpine 3.23, alpine 3.24

💅 Smokeping_probes_CiscoRTTMonDNS(3) — the SmokePing manual, bestie edition 🎀

okay so this is a page from the SmokePing manual set, and it's about Smokeping::probes::CiscoRTTMonDNS.pm — literally a probe for SmokePing. buckle up, it's giving router-girlie energy 🦋

✨ NAME ✨

Smokeping::probes::CiscoRTTMonDNS.pm — a Probe for SmokePing. periodt.

🌸 SYNOPSIS 🌸

*** Probes ***

+CiscoRTTMonDNS

forks = 5
offset = 50%
step = 300
timeout = 15

# The following variables can be overridden in each target section
/^influx_.+/ = influx_location = In the basement
ioshost = RTTcommunity@Myrouter.foobar.com.au # mandatory
iosint = 10.33.22.11
name = www.foobar.com.au # mandatory
pings = 5
timeout = 15

# [...]

*** Targets ***

probe = CiscoRTTMonDNS # if this should be the default probe

# [...]

+ mytarget
# probe = CiscoRTTMonDNS # if the default probe is something else
host = my.host
/^influx_.+/ = influx_location = In the basement
ioshost = RTTcommunity@Myrouter.foobar.com.au # mandatory
iosint = 10.33.22.11
name = www.foobar.com.au # mandatory
pings = 5
timeout = 15

💖 DESCRIPTION 💖

So this is a probe for smokeping that uses the ciscoRttMon MIB functionality — they call it the "Service Assurance Agent", or "SAA" for short — on Cisco IOS, and it times (recursive, type A) DNS queries to a DNS server. like, the router does the asking and we just sit there looking cute and timing it. no cap 🔥

👑 VARIABLES 👑

🎀 Supported probe-specific variables:

  • forks — Run this many concurrent processes at maximum, bestie. multitasking icon behavior.
    • Example value: 5
    • Default value: 5
  • offset — okay so if you run many probes concurrently you may want to prevent them from hitting your network all at the same time (rude, honestly). 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. the patience meter, basically.
    • 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. slay, organized data 💅
    • Example value: influx_location = In the basement
  • ioshost — The (mandatory) ioshost parameter specifies the Cisco router, which will send the DNS requests, as well as the SNMP community string on the router. so it's like community@router, iconic format.
    • Example value: RTTcommunity@Myrouter.foobar.com.au
    • This setting is mandatory.
  • iosint — The (optional) iosint parameter is the source address for the DNS packets. This should be one of the active (!) IP addresses of the router to get results — like, active, with the exclamation mark, don't come in with a dead IP. IOS looks up the target host address in the forwarding table and then uses the interface(s) listed there to send the DNS packets. By default IOS uses the (primary) IP address on the sending interface as source address for packets originated by the router.
    • Example value: 10.33.22.11
  • name — The (mandatory) name parameter is the DNS name to resolve. literally the whole point tbh.
    • Example value: www.foobar.com.au
    • This setting is mandatory.
  • 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. same deal as step, iykyk.
    • Example value: 5
  • timeout — How long a single RTTMonDNS 'ping' takes at maximum plus 10 seconds to spare. Since we control our own timeout the only purpose of this is to not have us killed by the ping method from basefork. 🫶 protective queen.
    • Example value: 15
    • Default value: 15

🌈 AUTHORS 🌈

Joerg.Kummer at Roche.com — the mastermind, we stan 💜

🧚 NOTES 🧚

🍓 host parameter

The host parameter specifies the DNS server, which the router will use. simple as that, bestie.

🎀 IOS VERSIONS

This probe only works with IOS 12.0(3)T or higher. It is recommended to test it on less critical routers first — like, do NOT debut this on the main character router first, pls 🙈

⭐ INSTALLATION

To install this probe copy ciscoRttMonMIB.pm to ($SMOKEPINGINSTALLDIR)/lib/Smokeping and CiscoRTTMonDNS.pm to ($SMOKEPINGINSTALLDIR)/lib/Smokeping/probes. two files, two homes, moving day 🦋

The router(s) must be configured to allow read/write SNMP access. Sufficient is:

snmp-server community RTTCommunity RW

If you want to be a bit more restrictive with SNMP write access to the router (highkey the responsible choice honestly), then consider configuring something like this:

access-list 2 permit 10.37.3.5
snmp-server view RttMon ciscoRttMonMIB included
snmp-server community RTTCommunity view RttMon RW 2

The above configuration grants SNMP read-write only to 10.37.3.5 (the smokeping host) and only to the ciscoRttMon MIB tree. The probe does not need access to SNMP variables outside the RttMon tree. gatekeeping done right 💅

💀 BUGS 💀

The probe does unnecessary DNS queries, i.e. more than configured in the "pings" variable, because the RTTMon MIB only allows to set a total time for all queries in one measurement run (one "life"). Currently the probe sets the life duration to "pings"*5+3 seconds (5 secs is the timeout value hardcoded into this probe). yeah it's extra, it's a known thing, it's living its life 😭

🔥 SEE ALSO 🔥

<http://oss.oetiker.ch/smokeping/>

<http://www.switch.ch/misc/leinen/snmp/perl/>

The best source for background info on SAA is Cisco's documentation on <http://www.cisco.com> and the CISCO-RTTMON-MIB documentation, which is available at:

<ftp://ftp.cisco.com/pub/mibs/v2/CISCO-RTTMON-MIB.my>

ngl bestie, read those links. the CISCO-RTTMON-MIB one especially — that's the whole personality of this probe right there 🫶

and that's the page!! written for SmokePing version 2.9.0, dated 2025-06-30 — go forth and time those DNS queries, you gorgeous nerd 🧚‍♀️✨💖

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