Check_nwc_health issue and no idea how to solve

After a really long time hi again :green_heart:

I’d like to monitor the network interfaces on an Icinga Master, so I do this by using check_nwc_health and --servertype=linuxlocal. For its VPN interface, everyting is running fine:

'/usr/lib/nagios/plugins/check_nwc_health' '--hostname' 'localhost' '--mode' 'interface-health' '--name' 'tun0' '--servertype' 'linuxlocal'

Output is as follows (I wrapped it up a bit):

OK - tun0 is up/up,
interface tun0 usage is in:0.02% (2157.52bit/s) out:0.03% (3127.45bit/s),
interface tun0 errors in:0.00/s out:0.00/s ,
interface tun0 discards in:0.00/s out:0.00/s ,
interface tun0 broadcast in:0.00% out:0.00%

So I try to do exactly the same with eth0:

'/usr/lib/nagios/plugins/check_nwc_health' '--hostname' 'localhost' '--mode' 'interface-health' '--name' 'eth0' '--servertype' 'linuxlocal'

But the confusing output is as follows (wrapped up again):

CRITICAL - interface eth0 usage is in:-2.52% (26386.53bit/s) out:-20.98% (220031.87bit/s),
eth0 is up/up,
interface eth0 errors in:0.00/s out:0.00/s ,
interface eth0 discards in:0.00/s out:0.00/s ,
interface eth0 broadcast in:0.00% out:0.00%

When using it on console with -vvvvvv I get something like this:

info: checking interfaces
broadcastInPercent: 0
broadcastOutPercent: 0
delta_ifInBits: 1195584
delta_ifInBroadcastPkts: 0
delta_ifInDiscards: 0
delta_ifInErrors: 0
delta_ifInMulticastPkts: 0
delta_ifInOctets: 149448
delta_ifInUcastPkts: 0
delta_ifOutBits: 12600248
delta_ifOutBroadcastPkts: 0
delta_ifOutDiscards: 0
delta_ifOutErrors: 0
delta_ifOutMulticastPkts: 0
delta_ifOutOctets: 1575031
delta_ifOutUcastPkts: 0
delta_timestamp: 27
ifAdminStatus: up
ifCarrier: 1
ifDescr: eth0
ifInBroadcastPkts: 0
ifInBroadcastPkts_per_sec: 0
ifInDiscards: 0
ifInDiscards_per_sec: 0
ifInErrors: 0
ifInErrors_per_sec: 0
ifInMulticastPkts: 0
ifInMulticastPkts_per_sec: 0
ifInOctets: 18715362381
ifInOctets_per_sec: 5535.11111111111
ifInUcastPkts: 0
ifInUcastPkts_per_sec: 0
ifIndex: eth0
ifOperStatus: up
ifOutBroadcastPkts: 0
ifOutBroadcastPkts_per_sec: 0
ifOutDiscards: 0
ifOutDiscards_per_sec: 0
ifOutErrors: 0
ifOutErrors_per_sec: 0
ifOutMulticastPkts: 0
ifOutMulticastPkts_per_sec: 0
ifOutOctets: 44538688103
ifOutOctets_per_sec: 58334.4814814815
ifOutUcastPkts: 0
ifOutUcastPkts_per_sec: 0
ifSpeed: -1048576
inputDiscardRate: 0
inputErrorRate: 0
inputRate: 44280.8888888889
inputUtilization: -4.22295464409722
maxInputRate: -1048576
maxOutputRate: -1048576
outputDiscardRate: 0
outputErrorRate: 0
outputRate: 466675.851851852
outputUtilization: -44.5056773998119
sysMaxSpeed: 10
info: interface eth0 broadcast in:0.00% out:0.00%

So for me it seems to be a miscalculation on plugin’s side? Anyone ever seen this behaviour?

Thank you for your ideas,


is this the first run of the plugin? It caches several data on disk, and takes a delta from it. Might be the case that this hits a negative rate, or an overflow of int32.

What kind of distribution and architecture is your Icinga master?


Thats your problem try to add --ifspeed to your command with the speed of the interface