Hi,

PRTG Newbie here who has gone through the knowledgebase but not found an answer yet. Apologies if re-asking the same thing again.

We have a small but geographically diverse network consisting on Cisco, Mikrotik routerboards, E1 Modems, various MUX, Motorola Canopy and other wired and wireless devices all supporting SNMP (all do not support netflow, sflow, etc.).

Our network is a mesh with OSPF running for redundancy with 2 or more links terminating onto same Client end devices. If we use ping sensors, they always are green (or up) as ping can always take the backup route. We figure that a particular link will show down if we monitor a particular interface on say a Mikrotik or Cisco for it being Up or down.

Question: How can we monitor specific interface (physical interface or VLAN) for status?

Thanks, Vivek

Article Comments

Hello,

have you tried changing Connection State Handling in the "Settings" of the SNMP Traffic Sensors? If the interface is physically broken the sensor will be down anyway. If only 0 Traffic is flowing, you would need to use error-limits.

best regards.


Aug, 2011 - Permalink

Thanks Torsten! Figured out a way to do it before the post went online.

What I did on my mikrotik is:
1) go to device details page (in this case mikrotik)
2) click add sensor
3) choose snmp
4) click snmp library
5) choose cisco interface oidlib
(something seems wrong when i use cisco oid lib for mikrotik, but it worked!!!)

6) created a custom sensor with following properties
if: 15/ if oper status 
(15 is the port number i wanted to monitor)
selected interface: IF-MIB/if: 15/ if oper status
unit string #
multiplication 1
division 1
(if my port goes down the ifoper status is 2 and reverts to 1 when my port comes up)
if value changes trigger change notification
(in my case notification was an email was generated)

Problem: my device/port did not turn red
to do that
7)  select the sensor and go to sensor details page
8) choose channels tab
9) select if oper status in list of available channels
10) enable limits
11) set upper error limit to 1
12) save

this makes my port go red when my port goes down

I dont know what i did, but it works! Any help on proper way to do this would be appreciated

There is no way to replicate this sensor to multiple devices and multiple ports, I have to do everything manually. I think I may be missing something small and will eventually figure it out.

thanks a ton, Vivek


Aug, 2011 - Permalink

Torstens way is the best. Used it. Simple and very easy to implement


Aug, 2011 - Permalink

Hi there, Torstens way is simple, but I'd like to get the OperStatus inside RMON as a Channel, because the simple solution consumes sensors and if I have 1800 Switch-Ports, I will consume twice the amount of sensors. Also I'm not able to differentiate on dormant ports. Dormant (5) ones are not critical to me (RSTP usage), but "Down" (2) Status may be. So I'd like to put dormant in warnings and down in error.


Jul, 2014 - Permalink

The ifOperStatus is not available as a channel in the RMON Sensors. If you need it as a sensor result, please use a Sensor Custom Sensor then for each interface to monitor the ifOperStatus.


Jul, 2014 - Permalink