Monitoring Netgear Switches: Interesting MIBs

At my job we have been introducing new switches and in terms of feature’s and cost we’ve gone with Netgear. Sure every vendor does have it’s sharp edges, but so far mostly I’ve been quite happy with them. I’ve been thinkering around with how to monitor them – since they do SNMP I studied their MIBs and have found out some things that might help. One major disadvantage compared to big vendors is that far less companies use them in production and thus monitor them – I haven’t been able to find a specialized plugin that would cover Netgear-specific items so this Is a quite note on what I’ve been able to find. This only covers the fully managed switches, I don’t know if their smart managed switches also partially run on FASTPATH.

Netgear = Broadcom FASTPATH
The fist  and most obvious thing that I’ve found was that not only the chips inside Netgear managed switches are from Broadcom (as did 3Com) but also the operating systems, in fact the MIB namings suggest that Netgear buys the base (Linux-based) switching OS from Broadcom which is called FASTPATH ( According to Google search, some Dell switches are also known to run a some sort of Broadcom FASTPATH.

Getting the right MIBsBe sure to get a set of MIBs matching the closest possible to your revision you run onto. Netgear seems to modify behaviour (so did Cisco) or the meaning of values, so be sure you get the matching MIB for your product! At least the naming for MIB’s seemed to stay consistent though.

MIB 8.x to 9.x/10.x
While some of the (now) older switches run 8.x firmware I’ve realized that this revision (and likely previous releases too) tend to have meaning of output values. 9.x and 10.x based switches seem to be more consistent to each other but I wouldn’t warrant for that.

The most interesting parts are in private MIBs
I’ve been more interested in environmental and STP status and although Netgear seems to implement BRIDGE-MIB I had to realize that the most valuable information about STP is only exposed through their private MIBs:

If you look after monitoring STP status or checking some configurations for switching, this is the MIB you’ll want to check some examples that I’ve found useful:

  • agentStpAdminMod: Returns 1 when STP is enabled (I guess you don’t want that to be disabled!)
  • agentStpForceVersion: Returns the configured STP mode Multiple, Rapid or even plain ol’ STP
  • agentStpCstPortForwardingState: Followed by .<ifIndex> it gives you the current forwarding state of an (R)STP port
  • agentStpMstPortForwardingState: Gives meaningful values about the switch in case you’r using MSTP

This is the MIB that has environmental values,  this shows to have stong differences between 8.x and 9.x/10.x based firmware so pay attention. For sure a GSM5212P (12-Port GE) doesn’t have the same (amount) of Fans than GSM7228P (Stackable 24 GE + 1 10GE)

Unfortunately on most models I’ve encountered, some OIDs are not meaningful (buggy?) and thus can’t be used for monitoring, either way, here are some OID I’ve found interesting:

  • boxServicesFanItemState: Depending on the model you’ll almost certainly have .1 as the first fan. Some switches have 2-3 or more fans so be sure to check .1.-n
  • boxServicesFanSpeed: Most often bogus as it seems (9.x)
  • boxServicesPowSupplyItemState: While .1 tends to be the main PSU, .2 tends to be the RPS connector (not present by default)
  • boxServicesTempSensorState: Some devices have more than .1 sensors, do a walkd to find it out.

As for Nagios or Icigina I haven’t been able to find plugins to monitor Netgear boxes I guess I’ll have to write my own checks. I hope to post some examples here.

May 6, 2013

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