First, install your patched snmpd(8) agent binary on the systems you aree monitoring. Then install the MIB files on your NMS (management workstation):
$ ls -al /usr/local/share/snmp/mibs/OPENBSD-* -rw-r--r-- 1 root wheel 1723 Aug 31 13:07 /usr/local/share/snmp/mibs/OPENBSD-BASE-MIB.txt -rw-r--r-- 1 root wheel 7500 Sep 23 17:46 /usr/local/share/snmp/mibs/OPENBSD-CARP-MIB.txt -rw-r--r-- 1 root wheel 34568 Sep 23 17:47 /usr/local/share/snmp/mibs/OPENBSD-PF-MIB.txt -rw-r--r-- 1 root wheel 4086 Mar 18 2007 /usr/local/share/snmp/mibs/OPENBSD-SENSORS-MIB.txtIn some environments, you may need to set the $MIBS environmental variable to explicitly force Net-SNMP libraries to load the MIBs
$ export MIBS="+/usr/local/share/snmp/mibs/OPENBSD-PF-MIB.txt:/usr/local/share/snmp/mibs/OPENBSD-SENSORS-MIB.txt:\
/usr/local/share/snmp/mibs/OPENBSD-CARP-MIB.txt:/usr/local/share/snmp/mibs/OPENBSD-BASE-MIB.txt"
Next, become familiar with the following Net-SNMP utilities (read the entire man page until it hurts):
snmpwalk(1), snmpget(1), snmpcmd(1), snmptable(1), snmptranslate(1)Next, try walking the mib w/ snmpwalk(1). An example of walking the Sensor MIB:
$ snmpwalk -v2c -c [community] [device] OPENBSD-SENSORS-MIB::sensorsMIBObjects | egrep "\.(2|4|5|6|7|8|9)" OPENBSD-SENSORS-MIB::sensorDescr.2 = STRING: "Internal" OPENBSD-SENSORS-MIB::sensorDescr.4 = STRING: "fan0" OPENBSD-SENSORS-MIB::sensorDescr.5 = STRING: "fan1" OPENBSD-SENSORS-MIB::sensorDescr.6 = STRING: "fan2" OPENBSD-SENSORS-MIB::sensorDescr.7 = STRING: "+2.5Vin" OPENBSD-SENSORS-MIB::sensorDescr.8 = STRING: "Vccp" OPENBSD-SENSORS-MIB::sensorDescr.9 = STRING: "Vcc" OPENBSD-SENSORS-MIB::sensorType.2 = INTEGER: temperature(0) OPENBSD-SENSORS-MIB::sensorType.4 = INTEGER: fan(1) OPENBSD-SENSORS-MIB::sensorType.5 = INTEGER: fan(1) OPENBSD-SENSORS-MIB::sensorType.6 = INTEGER: fan(1) OPENBSD-SENSORS-MIB::sensorType.7 = INTEGER: voltsdc(2) OPENBSD-SENSORS-MIB::sensorType.8 = INTEGER: voltsdc(2) OPENBSD-SENSORS-MIB::sensorType.9 = INTEGER: voltsdc(2) OPENBSD-SENSORS-MIB::sensorDevice.2 = STRING: "adt0" OPENBSD-SENSORS-MIB::sensorDevice.4 = STRING: "adt0" OPENBSD-SENSORS-MIB::sensorDevice.5 = STRING: "adt0" OPENBSD-SENSORS-MIB::sensorDevice.6 = STRING: "adt0" OPENBSD-SENSORS-MIB::sensorDevice.7 = STRING: "adt0" OPENBSD-SENSORS-MIB::sensorDevice.8 = STRING: "adt0" OPENBSD-SENSORS-MIB::sensorDevice.9 = STRING: "adt0" OPENBSD-SENSORS-MIB::sensorValue.2 = STRING: "39.00" OPENBSD-SENSORS-MIB::sensorValue.4 = STRING: "700" OPENBSD-SENSORS-MIB::sensorValue.5 = STRING: "600" OPENBSD-SENSORS-MIB::sensorValue.6 = STRING: "2336" OPENBSD-SENSORS-MIB::sensorValue.7 = STRING: "1.82" OPENBSD-SENSORS-MIB::sensorValue.8 = STRING: "2.05" OPENBSD-SENSORS-MIB::sensorValue.9 = STRING: "3.37" OPENBSD-SENSORS-MIB::sensorUnits.2 = STRING: "degC" OPENBSD-SENSORS-MIB::sensorUnits.4 = STRING: "RPM" OPENBSD-SENSORS-MIB::sensorUnits.5 = STRING: "RPM" OPENBSD-SENSORS-MIB::sensorUnits.6 = STRING: "RPM" OPENBSD-SENSORS-MIB::sensorUnits.7 = STRING: "V DC" OPENBSD-SENSORS-MIB::sensorUnits.8 = STRING: "V DC" OPENBSD-SENSORS-MIB::sensorUnits.9 = STRING: "V DC"The same results can be viewed as a relational table array:
$ snmptable -v2c -Cl -c [community] [host:161] OPENBSD-SENSORS-MIB::sensorTable
SNMP table: OPENBSD-SENSORS-MIB::sensorTable
sensorIndex sensorDescr sensorType sensorDevice sensorValue sensorUnits sensorStatus
1 "Remote" temperature "adt0" "0.00" "degC" unspecified
2 "Internal" temperature "adt0" "39.00" "degC" unspecified
3 "Remote" temperature "adt0" "0.00" "degC" unspecified
4 "fan0" fan "adt0" "700" "RPM" unspecified
5 "fan1" fan "adt0" "600" "RPM" unspecified
6 "fan2" fan "adt0" "2334" "RPM" unspecified
7 "+2.5Vin" voltsdc "adt0" "1.82" "V DC" unspecified
8 "Vccp" voltsdc "adt0" "2.04" "V DC" unspecified
9 "Vcc" voltsdc "adt0" "3.37" "V DC" unspecified
10 "+5V" voltsdc "adt0" "5.13" "V DC" unspecified
11 "+12V" voltsdc "adt0" "12.06" "V DC" unspecified
An example of fetching the CARP MIB table (the -Cl causes left alignment):
$ snmptable -v2c -Cl -c [community] [host:161] OPENBSD-CARP-MIB::carpIfTable carpIfIndex carpIfDescr carpIfVhid carpIfDev carpIfAdvbase carpIfAdvskew carpIfState 1 "carp10" 10 "vlan10" 1 99 master 2 "carp20" 20 "vlan20" 1 99 master 3 "carp21" 21 "vlan21" 1 99 masterOther tables with a large array of columns can be truncated (such as the Interface table - note that this is simply an enumeration of /usr/include/net/if.h):
$ snmptable -v2c -Cb -Cw 150 -c [comm] [host:161] IF-MIB::ifTable
SNMP table: IF-MIB::ifTable
Index Descr Type Refs Rules In4PassPkts In4PassBytes In4BlockPkts In4BlockBytes Out4PassPkts Out4PassBytes Out4BlockPkts Out4BlockBytes
1 "all" group 0 1 0 0 0 0 0 0 0 0
2 "carp" group 0 1 0 0 0 0 0 0 0 0
3 "carp10" instance 0 8 0 0 0 0 0 0 0 0
4 "carp20" instance 0 6 0 0 0 0 0 0 0 0
5 "carp21" instance 0 6 0 0 0 0 0 0 0 0
6 "egress" group 0 1 0 0 0 0 0 0 0 0
7 "em0" instance 0 1 58903 19438448 0 0 13185 3945016 0 0
8 "enc0" instance 0 1 0 0 0 0 0 0 0 0
9 "lo" group 0 1 0 0 0 0 0 0 0 0
10 "lo0" instance 0 1 947 244547 0 0 947 244547 0 0
11 "pfsync" group 0 1 0 0 0 0 0 0 0 0
12 "pfsync0" instance 0 1 0 0 0 0 0 0 0 0
13 "vlan" group 0 1 0 0 0 0 0 0 0 0
14 "vlan10" instance 0 8 625075226 360716252112 5250 563915 559452066 116656439151 0 0
15 "vlan20" instance 0 6 478218213 86100293352 3037 242547 543485078 299297890231 0 0
16 "vlan21" instance 0 6 76263648 29910496513 0 0 78119871 60855739027 0 0
17 "xl0" instance 0 1 64180 9193310 0 0 181716 21603871 0 0
A few notes about data types. The SNMP RFCs specify abstraction of OS/Vendor-specific data types into RFC-specified types.
Most values are of "Counter64" integer type, meaning they increment over time upward until they overflow or administrative command to reset the value is issued.
$ snmpget -v2c -c [comm] [host:161] OPENBSD-PF-MIB::searches.0 OPENBSD-PF-MIB::searches.0 = Counter64: 2324725824Others are of type "Guage", meaning that the values fluctuate:
$ snmpget -v2c -Pd -c [comm] [host:161] OPENBSD-PF-MIB::count.0 OPENBSD-PF-MIB::states.0 OPENBSD-PF-MIB::count.0 = Gauge32: 64 OPENBSD-PF-MIB::states.0 = Gauge32: 200000And other that have unpredictable types are strings (seen here as fan RPMs):
$ snmpget -v2c -c [comm] [host:161] OPENBSD-SENSORS-MIB::sensorValue.6 OPENBSD-SENSORS-MIB::sensorValue.6 = STRING: "2333"NOTE: MRTG will later safety translate strings to integers, as PERL is an untyped interpreted language. Either way, you'll often need to translate the prefix-format MIB identifier into an OID for use with MRTG:
$ snmptranslate -On -Td OPENBSD-SENSORS-MIB::sensorValue.2
.1.3.6.1.4.1.64512.2.1.2.1.5.2
sensorValue OBJECT-TYPE
-- FROM OPENBSD-SENSORS-MIB
SYNTAX OCTET STRING
MAX-ACCESS read-only
STATUS current
DESCRIPTION "The value the sensor is currently reporting."
::= { iso(1) org(3) dod(6) internet(1) private(4) enterprises(1) openBSD(64512) \
sensorsMIBObjects(2) sensors(1) sensorTable(2) sensorEntry(1) sensorValue(5) 2 }
As you can see, snmptranslate(1) can also be used to enumerate object "Descriptions" from ambiguously named objects (w/o picking through the cryptic MIB file)
$ snmptranslate -On -Td OPENBSD-PF-MIB::state-limit.0 .1.3.6.1.4.1.64512.1.2.13.0 state-limit OBJECT-TYPE -- FROM OPENBSD-PF-MIB SYNTAX Counter64 MAX-ACCESS read-only STATUS current DESCRIPTION "The number of packets that were dropped due to the per-rule max state limit being reached."As opposed to:
OPENBSD-PF-MIB::states.0 = Gauge32: 200000 ::
DESCRIPTION "The maximum number of entries in the memory pool used by state
table entries (filter rules that specify 'keep state')."
As you will find in MRTG, some object translate properly by their logical reference names:
$ sudo -H -u mrtg /usr/local/bin/mrtg --debug=snpo /usr/local/etc/mrtg/mrtg-br0-ng.conf 2>&1|more --snpo: SNMPGet from [comm]@[host]:::::2 -- pfsyncIpPktsRecv.0,pfsyncIpPktsSent.0,sysUptime,sysName --snpo: SNMPfound -- '58903', '13513', '12 days, 22:29:26.88', 'br0' --snpo: run snmpget from pfsyncNoMemory&pfsyncOutputErrors:[comm]@[host]Others fail inexplicably miserably translation due to MRTG's SNMP library:
--snpo: run snmpget from pfsyncNoMemory&pfsyncOutputErrors:[comm]@[host] --snpo: simple If: .0 --snpo: simple If: .0 --snpo: SNMPGet from [comm]@[host]:::::2 -- pfsyncNoMemory.0,pfsyncOutputErrors.0,sysUptime,sysName --snpo: SNMPfound -- 'undef', 'undef', '12 days, 22:33:03.60', 'br0'
Example MRTG Graph Template
pf(4) State Table Entries
pf(4) State Table Searches and/or pf(4) State Table Matches & Mis-Matches
pf(4) State Table Inserts & Removals
Screenshots:
pfsync(4) control IP packets
Target[br0.pfsyncPkts]: pfsyncIpPktsRecv.0&pfsyncIpPktsSent.0:[comm]@[host]:::::2 PageTop[br0.pfsyncPkts]: <H1>pfsync(4) control IP packets<H1> Title[br0.pfsyncPkts]: pfsync(4) control IP packets Options[br0.pfsyncPkts]: nopercent,noinfo,integer MaxBytes[br0.pfsyncPkts]: 999999999 #kMG[br0.pfsyncPkts]: YLegend[br0.pfsyncPkts]: Packets ShortLegend[br0.pfsyncPkts]: pkts LegendI[br0.pfsyncPkts]: pkts/s RX LegendO[br0.pfsyncPkts]: pkts/s TX Legend1[br0.pfsyncPkts]: Packets Legend2[br0.pfsyncPkts]: PacketsScreenshots:
pf(4) CARP Packets RX/TX
# PF number of OPENBSD-CARP-MIB::carpIpPktsRecv.0 && OPENBSD-CARP-MIB::carpIpPktsSent.0 #Target[br0_pf_carpPktsTX]: carpIpPktsRecv.0&carpIpPktsSent.0:[comm]@[host]:::::2 Target[br0_pf_carpPktsTX]: .1.3.6.1.4.1.64512.3.3.1.0&.1.3.6.1.4.1.64512.3.3.12.0:[comm]@[host]:::::2 Title[br0_pf_carpPktsTX]: pf(4) carp(4) Packets RX/TX PageTop[br0_pf_carpPktsTX]: <H1>pf(4) CARP Packets RX/TX<H1> LegendI[br0_pf_carpPktsTX]: Packets RX LegendO[br0_pf_carpPktsTX]: Packets TX Legend1[br0_pf_carpPktsTX]: Packets RX Legend2[br0_pf_carpPktsTX]: Packets TX YLegend[br0_pf_carpPktsTX]: Packets ShortLegend[br0_pf_carpPktsTX]: pkts Options[br0_pf_carpPktsTX]: nopercent, integer, perminute MaxBytes[br0_pf_carpPktsTX]: 900000000 WithPeak[br0_pf_carpPktsTX]: dwmy # Unscaled[myrouter]: dwmyScreenshots:
sensor(4) MIB ADT7460 Sensor CPU Temperature
Target[br0sensor_cpu]: .1.3.6.1.4.1.64512.2.1.2.1.5.2&.1.3.6.1.4.1.64512.2.1.2.1.5.2:[comm]@[host]:::::2 #Target[br0sensor_cpu]: sensorValue.2&sensorValue.0:[comm]@[host]:::::2 Title[br0sensor_cpu]: PF Sensor MIB ADT7460 Sensor CPU Temperature PageTop[br0sensor_cpu]: <H1>PF Sensor MIB ADT7460 Sensor CPU Temperature<h1> LegendI[br0sensor_cpu]: degC LegendO[br0sensor_cpu]: degC Legend1[br0sensor_cpu]: degC Legend2[br0sensor_cpu]: degC YLegend[br0sensor_cpu]: degC ShortLegend[br0sensor_cpu]: deg Options[br0sensor_cpu]: nopercent, integer, gauge MaxBytes[br0sensor_cpu]: 100000 WithPeak[br0sensor_cpu]: dw
sensor(4) MIB ADT7460 Sensor CPU Fan RPMs
Target[br0sensor_cpufanrpm]: .1.3.6.1.4.1.64512.2.1.2.1.5.6&.1.3.6.1.4.1.64512.2.1.2.1.5.6:[comm]@[host]:::::2 #Target[br0sensor_cpufanrpm]: OPENBSD-SENSORS-MIB::sensorValue.6 Title[br0sensor_cpufanrpm]: PF Sensor MIB ADT7460 Sensor CPU Fan RPMs PageTop[br0sensor_cpufanrpm]: <H1>PF Sensor MIB ADT7460 Sensor CPU Fan RPMs<h1> LegendI[br0sensor_cpufanrpm]: rpms LegendO[br0sensor_cpufanrpm]: rpms Legend1[br0sensor_cpufanrpm]: rpms Legend2[br0sensor_cpufanrpm]: rpms YLegend[br0sensor_cpufanrpm]: rpms ShortLegend[br0sensor_cpufanrpm]: rpms Options[br0sensor_cpufanrpm]: nopercent, integer, gauge, noo MaxBytes[br0sensor_cpufanrpm]: 100000 WithPeak[br0sensor_cpufanrpm]: dwScreenshots:
External Links:
ChangeLog
12/13/07: Init
Contact Me: bseklecki@collaborativefusion.com