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My monitoring system is using data from SNMP polls to build graphs. This works fine with a few dozen RHEL 6 and 7 hosts, but graphs for all my new CentOS 8 hosts are not working correctly. I've done some checking and the problem is with the ifSpeed MIB returning zero for all interfaces except lo:

$ snmpwalk -v 3 rhel6.foo.internal 1.3.6.1.2.1.2.2.1.5
IF-MIB::ifSpeed.1 10000000
IF-MIB::ifSpeed.2 1000000000
IF-MIB::ifSpeed.3 1000000000

$ snmpwalk -v 3 centos8.foo.internal 1.3.6.1.2.1.2.2.1.5
IF-MIB::ifSpeed.1 10000000
IF-MIB::ifSpeed.2 0
IF-MIB::ifSpeed.3 0

My snmpd.conf on both boxes is identical, the older systems are running net-snmp 5.7.2 versus 5.8.0 on the new ones. Is there any way I can configure the system to properly return an interface speed?

miken32
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1 Answers1

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Merely another bug in net-snmp abandonware. Report it. It already has a load of those.

But this has nothing to do with the graphs, ifSpeed is a consultational value (that's probably the reason nobody cares about it). Graphs are using counters, even from another table, that doesn't even have the ifSpeed oid - ifXTable. 32-bit counters from ifTable are buried in the past, where 100 MBit/s interfaces were in massive use.

drookie
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  • I don't know if you've ever taken a look at the Nagios/Icinga plugin world, but "buried in the past" applies there as well. It's using the `ifSpeed` value to calculate the max for the graph, and doesn't seem to work without it. – miken32 Oct 10 '21 at 14:32
  • Nagios/icinga network graphs ? REALLY ? Cacti was used for this these days (and MRTG before it) (and now grafana). You’re confusing things. Icinga/nagios don’t graph anything except availability. Both are purely monitoring software, where “monotoring” is equal for “alerting”. Switch to grafana, really. You're missing an entire topic in your professional resume. – drookie Oct 10 '21 at 14:36
  • All Nagios plugins can output performance data that 3rd party software uses to build graphs. This really isn’t relevant to the question though, which is about net-snmp – miken32 Oct 10 '21 at 15:22