TUT:Configuring snmptrapd to parse MIBS from 3rd party Vendors
AKA, "How the hell do I log Cisco-specific traps?"
Many agents/devices implement a variety of these default vendor-neutral MIBs (IF-MIB, etc.) as part of a compatibility package, but if you wish to communicate with vendor-customized MIB trees on a device, you must load the MIBs for that device from the vendor. For snmptrapd(8), traps with OIDs in trees not enumerated by the installed MIB files will show up in numeric format.
Commonly Requested MIBs
Installing Custom MIBs
snmptrapd behaves like all other Net-SNMP applications and conforms to the standard methods of finding and loading MIBs. The "Using and loading MIBS" tutorial goes into depth about how to configure a Net-SNMP application to load extra MIBs. In summary, it boils down to:
- Identify the MIBs for your platform/product
- Install them into your $MIBDIR
- Adjust your $MIB variable and restart the snmptrapd(8) binary
Identifying MIBs for your platform
The process is vendor-specific.
APC has one huge MIB for all of its product lines: PowerNet MIB
Cisco has approximately one thousand MIBs for various products:
seklecki@rampage:/home/seklecki$ echo ls | ftp -a ftp://ftp.cisco.com/pub/mibs/v2/ | wc -l 1084
To find the MIBs supported by your Cisco product, look in the technical appendix of each product and/or use the MIB browser tool. You will need to search by your firmware file name (if you do not have access to the console, ask your admin, or walk the device with the community string provided)
Example Cisco Catalyst 3548-XL:
To find your hardware ver:
cs0#sh version | include proc cisco WS-C3548-XL (PowerPC403) processor (revision 0x01) with 16384K/1024K bytes of memory.
To find your IOS/firmware filename:
cs0#sh flash: Directory of flash:/ 2 -rwx 1811552 Feb 28 1993 19:27:28 c3500xl-c3h2s-mz.120-5.WC17.bin
Once you search for your release, you will get an index of files that are required to meet various inter-MIB dependencies. Example Screehsot
You will also always need SNMPv2-SMI for all Cisco-related MIBs
Install the MIBs in $MIBDIR
Place the files with appropriate permissions and ownership in $PREFIX/share/snmp/mibs/. The file extensions from Cisco are .my. From APC its a .txt. Both are fine.
Activate the MIBs
snmptrapd_enable="YES" snmptrapd_flags="-a -p /var/run/snmptrapd.pid -Ls 2 -Lf /var/log/snmptrapd-direct.log -m ALL"
Make snmptrapd(8) generate usable logs:
For a long time, I routed snmpd(8) and snmptrapd(8) traps though syslog(8). However, most commercial systems (and packet dump/analysis tools) display traps as:
Header Var: Val Header Var: Val Header Var: Val OID1 - (Value) Format OID2 - (Value) Format OID3 - (Value) Format OID4 - (Value) Format ....
This format is much more machine and human-parseable.
logoption s 2 logoption f /var/log/snmptrapd-direct.log
format2 %V\n% Agent Address: %A \n Agent Hostname: %B \n Date: %H - %J - %K - %L - %M - %Y \n Enterprise OID: %N \n Trap Type: %W \n Trap Sub-Type: %q \n Community/Infosec Context: %P \n Uptime: %T \n Description: %W \n PDU Attribute/Value Pair Array:\n%v \n -------------- \n
Cisco Authentication Failure
Without Custom MIB
$ sudo tail -50 /var/log/snmptrapd-direct.log NET-SNMP version 5.4.1 2008-05-08 18:18:11 vlan12.as0.lab00.pitbpa0.priv.collaborativefusion.com [UDP: [192.168.3.6]:54394]: DISMAN-EVENT-MIB::sysUpTimeInstance = Timeticks: 812050957) 93 days, 23:41:49.57 SNMPv2-MIB::snmpTrapOID.0 = OID: CISCO-SMI::ciscoMgmt.184.108.40.206 CISCO-SMI::ciscoMgmt.220.127.116.11.1.3.96 = INTEGER: 1 CISCO-SMI::ciscoMgmt.18.104.22.168.1.4.96 = INTEGER: 3 CISCO-SMI::ciscoMgmt.22.214.171.124.1.5.96 = INTEGER: 4
With Custom MIB
$ sudo tail -50 /var/log/snmptrapd-direct.log NET-SNMP version 5.4.1 Agent Address: 0.0.0.0 Agent Hostname: vlan12.as0.lab00.* Date: 21 - 56 - 21 - 17 - 6 - 1991 Enterprise OID: . Trap Type: Cold Start Trap Sub-Type: 0 Community/Infosec Context: TRAP2, SNMP v2c, community foo Uptime: 0 Description: Cold Start PDU Attribute/Value Pair Array: DISMAN-EVENT-MIB::sysUpTimeInstance = Timeticks: (812034228) 93 days, 23:39:02.28 SNMPv2-MIB::snmpTrapOID.0 = OID: CISCO-CONFIG-MAN-MIB::ciscoConfigManEvent CISCO-CONFIG-MAN-MIB::ccmHistoryEventCommandSource.93 = INTEGER: commandLine(1) CISCO-CONFIG-MAN-MIB::ccmHistoryEventConfigSource.93 = INTEGER: running(3) CISCO-CONFIG-MAN-MIB::ccmHistoryEventConfigDestination.93 = INTEGER: startup(4) --------------
As you can see, the later configuration is a significant improvement.
Note: Logging with the improved format to the syslog does not improve the situation, as line-feed+carriage return characters are translated.
This page to be created on 05/06/2008 by Brian A. Seklecki