Friday 23 January 2015

Minimal SNMP View for Solarwinds Management of a Cisco Device

Some time ago, I was asked to provide a customer read-only SNMP access to a router so that they could monitor bandwidth utilisation. Unfortunately the device had some sensitive configuration which needed to be protected, so giving access to the full MIB was not an option. With that in mind, I set up an SNMP view which permitted access to the ifMIB and nothing else, thinking that would be sufficient to monitor interface usage.

The customer tested and soon came back to advise me that, although he could successfully run an SNMP walk, his Solarwinds NMS could not discover the device and therefore he couldn't get the stats he needed.

It turns out that Solarwinds needs a particular set of OIDs to be visible before it will allow a device to be discovered and brought under management. There are a few articles on the knowledge base about which OIDs it uses for various purposes, e.g:

http://knowledgebase.solarwinds.com/kb/questions/1196/

However, there doesn't seem to be one directly addressing the question of which OIDs are required just to bring a device under management.

Eventually I think I gave up and sniffed a discovery off the wire and looked at which OIDs it used -  I don't exactly remember any more. Anyway, here is a list that seems to do the trick. The following CLI should configure a minimal set of OIDs on a Cisco device:

snmp-server view STATS iso excluded
snmp-server view STATS mib-2 excluded
snmp-server view STATS cisco excluded
snmp-server view STATS system.1.0 included
snmp-server view STATS system.2.0 included
snmp-server view STATS system.4.0 included
snmp-server view STATS system.5.0 included
snmp-server view STATS system.6.0 included
snmp-server view STATS ifIndex included
snmp-server view STATS ifDescr included
snmp-server view STATS ifSpeed included
snmp-server view STATS ifOperStatus included
snmp-server view STATS ipAddrEntry.2 included
snmp-server view STATS lsystem.8 included
snmp-server view STATS lsystem.58 included
snmp-server view STATS chassis.6 included
snmp-server view STATS ifName included
snmp-server view STATS ifHCInOctets included
snmp-server view STATS ifHCInUcastPkts included
snmp-server view STATS ifHCInMulticastPkts included
snmp-server view STATS ifHCInBroadcastPkts included
snmp-server view STATS ifHCOutOctets included
snmp-server view STATS ifHCOutUcastPkts included
snmp-server view STATS ifHCOutMulticastPkts included
snmp-server view STATS ifHCOutBroadcastPkts included
snmp-server view STATS ifHighSpeed included
snmp-server view STATS ifAlias included
snmp-server view STATS ciscoMemoryPoolEntry.5 included
snmp-server view STATS ciscoMemoryPoolEntry.6 included
snmp-server view STATS cpmCPUTotalTable.1.5 included
snmp-server view STATS cpmCPUTotalTable.1.8 included

Once the view is defined, you just need to apply it to the particular community string for SNMPv2:

snmp-server community mycomm view STATS RO

Or the user for SNMPv3:

snmp-server group Monitoring v3 priv read STATS write STATS

This config allowed SolarWinds to discover the device and bring it under management. It also allowed basic port stats to be collected and general up/down alarms to be raised.

Of course, you can add more OIDs into the "included" list as needed for your particular use case, however these should be enough for SolarWinds to discover the device.

No comments:

Post a Comment